In one of the first takes of Hermione's "Cinderella moment", Emma Watson actually tripped in that fancy dress and fell down the stairs.

Mike Newell was not aware that Alan Rickman wore black contact lenses for the role of Snape until one day, when he was complimenting Alan on the amazing shade of his eyes, Alan leaned over and popped one of the lenses out.

The underwater scenes were shot in a huge purpose-built tank with a blue-screen background. Safety divers swam in-between takes with scuba regulators, to allow the actors to breathe without having to surface. Daniel Radcliffe alone logged around 41 hours and 38 minutes underwater during the course of filming. At one point, during training, he inadvertently signaled that he was drowning, sending the crew into a huge panic to bring him back up to surface.

At least one full-scale dragon was constructed on set, which could even blow real fire. The dragon was created partially from the basilisk puppet seen in Harry Potter and the Chamber of Secrets (2002).

(at around 39 mins) Icelandic moviegoers (particularly the younger crowd) tended to crack up unexpectedly in theaters, when Rita Skeeter first introduces herself. Apparently, the audience weren't expecting the pronunciation of her last name, Skeeter, to sound so close to the Icelandic verb "skíta", which happens to be a rather crude word for defecating.

Mike Newell decided against the studio's original idea of adapting the extremely long book into two separate films to be released several months apart, figuring that he could cut enough of the book's bulky subplots to make a workable film. It was Alfonso Cuarón, the director of Harry Potter and the Prisoner of Azkaban (2004), who convinced him.

The books that form Dumbledore's library, are actually phone directories in disguise.

During the underwater filming, Daniel Radcliffe, a couple of the cast members, and all of the underwater crew, posed for a photo, which he later sent out as a Christmas card, with Rudolph's nose and antlers Photoshopped on everyone's faces.

Early drafts had Ron's estranged brother Percy appearing in a key supporting role but it was written out in the final drafts. In an interview, Chris Rankin, who plays Percy, revealed that his contract of the franchise stipulates that he must appear in four films; the first three, with the option of appearing in either this movie or the next one, Harry Potter and the Order of the Phoenix (2007). Given the fact that Percy appears much longer in the latter, he opted out of the film in favor of appearing in the next one.

Costume designer Jany Temime considered Hermione's dress for the Yule Ball as the most important, comparing it to that of Cinderella. The design of the dress was changed several times, before the designers were satisfied with the results. Emma Watson was very careful not to wear it more than necessary, because she was afraid that she would wreck it.

(at around 6 mins) The elves Dobby and Winky were cut due to time constraints. However, if you watch carefully in the first campsite scene, right after Ginny points to something and says "Look!" you can see two House Elves riding on llamas. They go by very fast, so they're hard to see.

In the movie, the audience is given the impression that Beauxbatons is an all-girls academy, whereas Durmstrang is an all-boys one. In the book, however, both schools are co-ed, and in fact, in the book, the Patil twins leave Harry and Ron, to spend time with boys from Beauxbatons.

In the books, Parvati Patil of Gryffindor has an identical twin Padma Patil of Ravenclaw, to illustrate the unpredictability of the Sorting Hat. In the films, however, Parvati (Shefali Chowdhury) and Padma (Afshan Azad) are not only both in Gryffindor but are played, surprisingly, by unrelated actresses.

The first film of the franchise to not open with a "Harry-centric" scene. Staying true to the book, it opens with The Riddle House, a "Voldemort-centric" scene.

Final Harry Potter film to feature scenes filmed at the University of Oxford. Oxford inspired much of the architecture of Hogwarts including the Great Hall.

During the course of filming, Daniel Radcliffe matured a lot physically. In an interview, Mike Newell remarked "I've just been working on a scene which we shot in our first week, and Dan still looks like the little kid that he was in Sorcerer's Stone. Now, eleven months later, he doesn't look like that at all."

The kids had around three weeks of dancing practice for the Yule-ball waltz. Daniel Radcliffe, however, appears in almost every scene of the entire film, and thus had only four days to prepare for this task. In several interviews, he has given that reason for why his dancing is shown mainly from the waist up (to avoid showing his fumbling feet). Fortunately, this wasn't a huge issue, as Harry wasn't supposed to be a brilliant dancer anyway.

While filming his scenes as Professor Dumbledore, Michael Gambon wore street clothes under his flimsy costume. He also kept his cigarettes tucked into his socks.

(at around 51 mins) Moody's line "I know stories about your father that would curl even your greasy hair," is actually paraphrased from a line in the book, but used in a different scenario: Rita Skeeter originally said it to Hermione about Ludo Bagman (a character omitted from the movie).

Mike Newell only received one million dollars to direct (whereas Chris Columbus received ten million dollars, plus a percentage of the gross to direct Harry Potter and the Sorcerer's Stone (2001)).

Daniel Radcliffe suffered two ear infections following the underwater filming.

Mike Newell staged a brawl with one of the Weasley twins, both to demonstrate what he wanted for a scene between them, and also to undermine his own "authority figure" status ("They were calling me 'sir'!") The fight got so intense, that he fractured a rib in the process.

Mike Newell originally decided not to have the make-up on Ralph Fiennes to give a more scary Voldemort. But he changed his mind after seeing a minimal make-up design by Nick Dudman. To complement the make-up, Fiennes shaved his head, as well as his armpits.

The first task with the dragon took over 140 visual effect shots. Some brief parts of it are entirely digital, including not just the dragon, but also the whole environment, and even Harry himself.

(at around 1h 45 mins) In the scene with Dumbledore, Harry, and the Pensieve, pay close attention to the glass cabinet Dumbledore approaches while explaining the Pensieve. In the top left corner is a 3D model of what becomes an important symbol in the final novel, Harry Potter and the Deathly Hallows.

Katie Leung hadn't intended to audition for the role of Cho Chang. Her father had told her where the audition was being held, and she decided to go before her shopping trip.

Features one of the largest underwater sets ever constructed. It has the capacity of up to 500,000 liters (132,000 gallons) of water. The largest underwater set constructed was for The Abyss (1989), which had a capacity of 26,497,882 liters (seven million gallons).

When he first signed on to direct, Mike Newell explained to David Heyman that he wanted to make a "Bollywood film". While this had him a little skeptical at first, Heyman understood what he meant. "There is no singing and dancing, but of all the films, Goblet of Fire has the most colors," Heyman said. "There's teenage romance, the glamorous Yule Ball, the theatrical Quidditch World Cup, and the spectacular Tri-wizard Tournament."

Mike Newell wanted the Dark Mark to "bubble up" out of the skin of Voldemort's followers. The makeup department achieved the effect by applying variations of a silicone skull-and-snake to each actor's arm, gradually making the mark appear more "raised and angry looking". Digital effects were then used to create the snake's movement.

The animated hedges in the Third Task were based on Stanley Kubrick's abandoned idea for the hedge maze chase sequence in The Shining (1980). "The Shining" was written by Stephen King, who is an avid fan of "Harry Potter" author J.K. Rowling.

As Ron, Harry, and Hermione are talking in the great hall, before George and Fred attempt to enter their names in the Goblet, Hermione is reading a book. We can't see the title, but the cover features the harlequin pattern of the UK editions of the Harry Potter novels.

The rock band at the Yule Ball is comprised mostly of members of Pulp and Radiohead. In the run-up to the movie, a Canadian folk group called the Wyrd Sisters filed a forty million dollar lawsuit against Warner Brothers, the North American distributor of the film, Jarvis Cocker from Pulp, and Jonny Greenwood and Phil Selway, of Radiohead for the use of their group's name. In the book, the band is called the "Weird Sisters", after the witches in William Shakespeare's "Macbeth", but was reportedly renamed the "Wyrd Sisters" for this film. Before the movie was released, however, Warner Brothers removed all references to either name for the band. (In a deleted scene included on the DVD, Professor Flitwick introduces the band as "The band that needs no introduction.") Nevertheless, the Wyrd Sisters moved for an injunction in a Canadian court to prevent distribution of the film in Canada. This motion was dismissed by an Ontario judge.

The tune you hear the teens sing to the school song, "Hogwarts, Hogwarts, Hoggy Warty Hogwarts" is traditionally sung to any tune the singer happens to like, but for the sake of clarity this has been changed to a chain-song with a fixed melody in the film. The song performed that way in its entirety can be heard in a deleted scene on most home video releases, lyrics first appeared in the first novel, "Harry Potter and the Philosopher's/Sorcerer's Stone".

In the book, Voldemort is described as having red eyes with slits for pupils. The filmmakers ultimately decided not to give Voldemort red eyes, because they felt that one wouldn't be able to read the emotion in the eyes if they were modified, and therefore the character wouldn't be scary enough. If you look closely during his final reformation stages, he opens his eyes just before it's fully completed, and very briefly his pupils are indeed like slits rather than human pupils.

The only Harry Potter film not to feature Julie Walters.

Henry Cavill auditioned for the role of Cedric Diggory.

(at around 1h 5 mins) The character Nigel, who appears in this film, and Harry Potter and the Order of the Phoenix (2007), does not appear in the books at all. Given his short stature, and apparent idolizing of Harry, it seems likely that he is meant to act as a substitute for Colin Creevey (from Harry Potter and the Chamber of Secrets (2002)) and his brother Dennis (who is introduced in the Goblet of Fire book).

Only one of the actresses portraying French characters speak with a natural French accent (Clémence Poésy), Clemence Poesy was born and raised in France, and the actress who plays Madame Maxine is from England.

The newspaper headline "Harry Potter and the Triwizard Tournament" was considered as the title of the fourth book.

This is the first movie to not show the Dursleys. They were featured in the book in the very beginning, where they are visited by the Weasley family, who come to pick up Harry for the Quidditch World Cup. This was omitted from the movie, because the actors portraying the Dursleys demanded more money, so they were cut, and this is why Harry is shown spending the night at the Weasleys' just before the Quidditch World Cup.

In the novel, Hermione uses the Sleekeazy's Hair Potion, a hair care potion, to straighten her hair for Yule Ball. J.K. Rowling would later reveal on Pottermore, as part of the Potter family background, that this potion was invented by Fleamont Potter, paternal grandfather of the title character, Harry Potter.

The film's reels were shipped to cinemas under its working title "Happy Days" to deter potential pirates.

Rosamund Pike was the first choice for the role of Rita Skeeter, but declined.

(at around 1h 50 mins) When the contestants enter the arena for the third task, the Beauxbatons girls in the audience are dancing the Macarena.

Although it is not explained in the movie, Fleur Delacour is described as part Veela in the books. Veelas in the Potterverse are magical nymph-like beings that have the ability to charm men. Fleur actually has a strand of her Veela grandmother's hair as the core of her wand.

A digital "spot removing" technique (which had previously been used for such television shows as Desperate Housewives (2004)) was applied in post-production to clear up some of the more severe teen skin problems, since make-up tested poorly for close-up shots in particular.

(at around 25 mins) The creature Mad-Eye Moody torments in his "dark arts" class (a spider in the book and the original script) is virtually identical to a real animal: the tailless whip-scorpion. Tailless whip-scorpions, of which some 130 species are known, fall in their own taxonomic order 'Amblypygi' under Class 'Arachnida', and are neither scorpions or spiders. Though Moody avers that this one is deadly, real Amblypygids are quite harmless (though almost as big).

John Williams passed on scoring this movie in favor of Memoirs of a Geisha (2005).

The ice sculptures at the Yule Ball were made of resin (as real ice obviously would melt). Though the resin was clear, it appeared pink beneath the white stage lighting. To solve this issue, blue lighting gels were used to turn it icy blue.

Alfonso Cuarón was offered the chance to direct this installment in the franchise, but declined, as he would still be working on the post-production for Harry Potter and the Prisoner of Azkaban (2004).

This is the first Harry Potter film to receive a "PG-13" rating or its international equivalent (for sequences of fantasy violence and frightening images). The preceding films having been rated "PG" or one of its international equivalents.

The inscriptions on the Riddle's family tombstone had to be digitally changed at the last minute after fans of the books, having seen promotion stills released from the graveyard scene, pointed out that none of the Riddle names on the tombstone referred to Voldemort (a.k.a. Tom Marvolo Riddle), as the filmmakers erroneously thought, but to his dad, Tom Riddle (Sr.), his grandfather, Thomas Riddle, and his grandmother, Mary Riddle.

(at around 1h 35 mins) After the second task, as Dumbledore magnifies his voice, his wand can be seen with a white band on it that bears the mark of a straight line atop a few lines in a criss cross pattern all atop a circle, which will all be important plot elements in future installments.

(at around 7 mins) In the movie, the Weasleys have really high seats at the Quidditch World Cup. The Malfoys make fun of them for being so high up in the "nosebleed section." In the book, however, the Weasleys have just as good as or even better seats than the Malfoys. The tickets were given to Arthur Weasley by Ludo Bagman at the Ministry of Magic, whose character is cut out of this movie due to time. Ludo's character is also a degenerate gambler, and throughout the book, tries to help Harry cheat in the Triwizard tournament; Harry refuses his help.

Daniel Radcliffe, arguably, looks more like the book version of Harry Potter in this film, as his hair in the film is the longest and messiest in the entire franchise. In the book series, Harry Potter is said to have long and messy hair.

It took two days to film Ralph Fiennes's role .

Tolga Safer was one of the finalists for the role of Viktor Krum. He was subsequently called back and instead cast as Karkaroff's aide, a role created specifically for him.

The name of "Durmstrang Institute" appears to be paying homage to the "Sturm und Drang" (translation: Storm and Stress) movement in German literature. The movement, which flourished from around 1770 to 1785, was distinguished by its theme of youthful genius in rebellion against accepted standards, much like Harry and his feelings about the wizarding world's attitude toward the Dark Lord.

(at around 1h 50 mins) When Harry is entering the maze, Mad Eye signals him that he should turn to his left. There is a wide belief that if one keeps turning left in a maze, he or she shall find his or her way out.

Over 3,000 girls turned up at the auditions for the role of Cho Chang in London on February 7, 2004.

As with the petrified figures in Harry Potter and the Chamber of Secrets (2002), full-sized models were used for the underwater scenes which required the charmed teen actors to keep completely still.

The walls of the Great Hall were covered in highly-reflective silver Lurex fabric for the Yule Ball sequence. Originally paint was going to be used, however, it was too flat, and did not have the desired effect. The same material was also used to create the curtains.

Mike Newell turned down directing The Constant Gardener (2005) to direct this film. Coincidentally, Ralph Fiennes appears in both films.

In the first draft of the script, a subplot featuring the Weasley twins and Ludo Bagman, the head of the Ministry's sports department, was featured prominently. In fact, it was reported that Martin Landham was cast as Bagman. In the subsequent drafts, the subplot was dropped, and the character of Ludo Bagman makes no credited appearance in the movie.

This is Robert Pattinson's (future Twilight Saga star's) first movie.

The first names of the parents of Tom Riddle (sr.) - Thomas and Mary, as written on the gravestone - are not mentioned in the books (but do still come from J.K. Rowling).

Mike Newell is the first English director the film franchise has had.

Rumors on the Internet of a Scottish actor being cast as Viktor Krum were halted, when it was announced that, as originally planned by the producers, a Bulgarian would in fact play the part. Perhaps these rumors arose because the Bulgarian was discovered in England, and not in Sofia, where there was a casting call for the part of the International Quidditch Champion. Stanislav Yanevski, a Bulgarian student living in London, had been cast in the role.

For Mad-Eye Moody, they used straps to conceal the wires that moved his fake eye, and to keep the mechanical eye in place.

In the extended version of the movie, that airs on ABC Family, when Harry is questioned by Snape about stealing from his potion/ingredient closet after Snape says "Boomslang Skin?" "Lacewing Flies?" Snape shuts the door on Harry. The line "You and your little friends are brewing Polyjuice Potion, and believe me, I'm going to find out why." is omitted from this version, but appears on the DVD.

Cho Chang became Scottish when Katie Leung was cast, allowing the actress to use her natural accent. Barty Crouch Jr. also became Scottish because the actor who plays him, David Tennant is Scottish.

Carole Bouquet was Mike Newell's first choice for the role of Madame Maxime, but declined because Studio Canal (the studio she was contracted) refused to give permission for her to negotiate for the role. Others considered for the role were Catherine Deneuve, Audrey Tautou, Emmanuelle Seigner, and Kate Winslet.

Only movie to not contain Hermione casting a spell.

Ray Winstone and Billy Connolly were considered for the role of Mad-Eye Moody.

First film in the franchise to not include any scenes from a Quidditch match in Hogwarts. No Quidditch matches take place in the book because of the Triwizard Tournament.

Currently, the DVD holds the Guinness World Record for being the fastest selling DVD of all time. The achievement was added to the 2007 book edition of The Guinness World Records, which includes a picture of the award being presented to Daniel Radcliffe on the set of Harry Potter and the Order of the Phoenix (2007) at Leavesden Film Studios in April 2006.

Brendan Gleeson and Daniel Radcliffe were both in The Tailor of Panama (2001), Radcliffe's first movie role.

(at around 18 mins) When the Durmstrang students make their entrance, several of them are demonstrating the Afro-Brazilian martial art Capoeira.

Scottish band Franz Ferdinand was the first choice to perform as the Weird Sisters, but they declined. Due to the similarities in name, the Canadian band Wyrd Sisters attempted to stop the film's release in Canada, by filing a lawsuit, but were unsuccessful.

Unlike the book, the spider being tortured by Mad-Eye Moody is heard making squealing sounds, which Harry imagined in the book, if the spider could make a sound.

In the novel, Hermione Granger wears a periwinkle blue dress to the Yule Ball. In the film, she wears a pink dress instead, as it was felt that a blue dress would not have stood out well enough against the blue background chosen for the Yule Ball sequence. Some fans disliked the change, as they felt the pink dress color did not suit the character. Also, the costumer designer felt that blue didn't suit Emma Watson.

In this film, when Harry looks in the Pensieve, it's as if he is actually in the memory, whereas in all subsequent films, whenever he looks in the Pensieve, he's only watching the memories.

Brendan Gleeson wore a wig while portraying Mad-Eye Moody. The wig concealed the electronics which made the magical eye move.

According to rumors that circulated the Internet, both Rowan Atkinson and John Malkovich were considered for the role of Lord Voldemort. Both rumors were proven to be untrue.

When Harry's warning Cedric about the first task being dragons, Seamus can be overheard talking to Ron about how he manages to blow objects up, a running gag of his in all the Harry Potter films.

(at around 1h 17 mins) Many fans and critics mocked Hermione's "Cinderella" entrance to the Yule Ball in comparison to the original novel, as it was felt that Emma Watson was simply too cute for the intended "butterfly effect" from the novel to be effective, even considering it unintentionally silly. Even Daniel Radcliffe mocked the film's handling of the scene, saying his co-star Watson, who is known for being a style and fashion nut, looked the same as before.

This film features five actors who have played Prime Minister Winston Churchill. Robert Hardy played him in War and Remembrance (1988), among several other films; Timothy Spall played the part in Jackboots on Whitehall (2010) and The King's Speech (2010); Brendan Gleeson played him in Into the Storm (2009). Michael Gambon played him in Churchill's Secret (2016) (TV), and Gary Oldman played him Darkest Hour (2017). Miranda Richardson plays Clementine Churchill in Churchill (2017).

The dragon faced by Harry is no dragon at all. As it does not have front legs, it is clearly a wyvern. Although the two are often confused, wyverns have two back legs and wings coming out of where their front legs would be, and dragons have two sets of legs plus wings coming out of their back. Wyverns generally are considered lesser cousins of the dragons, and are often unable to breathe fire. Another cousin of the dragon is the drakon, appearing identical to dragons, only lacking wings. These were originally considered for the book, but were eventually replaced with a more familiar dominating mythical creature.

In the Japanese dub, The Unforgivable Curse "Crucio" is pronounced "Kurushio", which is extremely close to the Japanese word "kurushi" meaning suffering.

Shares the same release date (November 18th) as Fantastic Beasts and Where to Find Them (2016), with an 11 year difference.

The members of the "Weird Sisters" were played by: Jarvis Cocker (of the band Pulp) as "Myron Wagtail" (vocals), Jonny Greenwood (of Radiohead) as "Kirley McCormick" (lead guitar), Jason Buckle (of All Seeing I) as "Heathcote Barbary" (rhythm guitar), Steve Mackey (also of Pulp) as "Donaghan Tremlett" (bass), Steve Claydon (of Add N to (X)) as "Gideon Crumb" (keyboards and bagpipes), and Phil Selway (also of Radiohead) as "Orsino Thruston" (drums).

The grindylow is a name for a type of water demon said to grab little children from the edge of a body of water and drown them. The term is used in the folktales of Yorkshire and Lancashire.

Unlike the other dragons from the First Task which are shown in the 'modern' wyvern design, the Common Welsh Green selected by Fleur is depicted in the classic dragon design with four legs.

First film in the series not to be dubbed into Icelandic (and other languages alike), where dubbing for theatrical release is limited to projects primarily aimed at children. In fact, even with different ratings of the following films, dubbing did not resume for some of those languages (like Icelandic).

David Walliams was considered for the role of Barty Crouch, Jr. He turned it down, due to his commitment to the television series Little Britain (2003).

Mike Newell was previously considered to direct Harry Potter and the Sorcerer's Stone (2001).

Unlike the book the pupils from the two visiting schools arrive on the first day of term rather than October. Plus the goblet chooses the champions later that week rather than Halloween.

Dumbledore unlike the other films of the franchise either screams or raises his voice in certain scenes such as when Harry was selected by the goblet of fire, when he asked Harry if he put his name in the goblet of fire and confronting Barty Crouch junior when he was posing as Mad Eye Moody. This was heavily criticized by many Harry Potter fans as Dumbledore was meant to be a calm and laid back character.

Mark Williams, Roger Lloyd Pack and David Tennant were all on Doctor Who (2005). Tennant played the tenth Doctor, Lloyd Pack played John Lumic in Doctor Who: Rise of the Cybermen (2006) and Doctor Who: The Age of Steel (2006) and Williams played Rory's father Brian in season 7.

Michael Gambon, Maggie Smith and David Tennant have previously worked together in the film "The Last September".

(at around 7 mins) When Harry passes inside of the Weasley's cabin (during the Quidditch's Mundial), he discovers that it's bigger inside than outside. The same idea was shown in Doctor Who (1963) with the TARDIS. David Tennant, who plays Barty Crouch, Jr., was the tenth Doctor in Doctor Who (2005).

M. Night Shyamalan was considered to direct the film, but turned it down.

"I can touch you now."-spoken by Lord Voldemort when he's touching Harry's forehead, is Ralph Fiennes favorite line throughout the Harry Potter movie series.

Chris Columbus, the director of the first two Harry Potter films, was amazed how beautifully Daniel Radcliffe, Emma Watson, and Rupert Grint matured over the franchise, compared to some child actors, who start out adorable, and then either lose that, or become bad actors as they grow older.

Besides Harry against the Hungarian Horntail during the first task, the way the other contestants defeat their dragon is revealed in the novel. Cedric against the Swedish Short Snout, used a Transfiguration spell to change a rock into a dog to distract the dragon he was partially successful as the dragon took the bait as Cedric went for the golden egg halfway through the dragon turn its attention and burned his face however Cedric still retrieved the egg and passed the task. Fleur Delacour against the Common Welsh Green, she enchanted the dragon to sleep but while retrieving the golden egg the dragon snored and let out a jet of flame that set her skirt alight. She extinguished the flames and retrieved her egg, Viktor Krum against the Chinese Fireball used the Conjunctivitis Curse to blind the dragon however he was docked points when the dragon stumbled and smashed half of the real eggs.

The maze lacks all of the obstacles in the book. Instead, the hedge maze itself is the obstacle, as it seems to be alive: it contracts and moves at random patterns, as well as reacting to and attacking the champions, especially if they stand still for too long. Also, the maze seems to occupy all the valley next to the Castle, instead of just the Quidditch Pitch.

From this film on, whenever a student or staff member was required to drink a potion, they were given soup. According to the cast, the top two flavors were carrot and coriander.

In the film adaptation of this the grindylow is a small creature with tentacles and two dangling tentacles on its head. In the book, there is no such description. The books also describe Grindylows as sickly green in colour; the movies depict them as beige. Originally, the grindylow were meant to be more like Angler Fish.

The second Harry Potter film to be the highest-grossing movie worldwide the year it was released. The first was Philosopher's Stone in 2001 and the third was Deathly Hallows Part 2 in 2011.

The incantation of the killing curse as introduced in this film, "Avada Kedavra", is one of very few spells that author Rowling lifted from existing sources, which she claims is ancient Aramaic and a precursor of the still well known "Abra kadabra" phrase, with its literal meaning being "Let it be destroyed".

This is the only film in which Polyjuice Potion is shown to replicate the voice and speech patterns of a person. In the other films where it's used, the person who took the potion still retains their own voice.

Chris Columbus has a figure of Dobby the Elf in his office.

Heart Evangelista auditioned for the role of Cho Chang.

The Hungarian Horntail's manner of breathing fire by shooting a pair of chemical liquids that cause a fire blast on contact is possibly based on the same fire-breathing manner used by dragons in the movie Reign of Fire (2002)

Caio Cesar, a prominent Brazilian voice actor, who dubbed Daniel Radcliffe as Harry Potter, was also a military cop. He died at the age of 27 in 2015 after being shot in his neck, at the Complexo do Alemão slums in Rio de Janeiro.

Shirley Henderson (Moaning Myrtle) & Matthew Lewis (Neville Longbottom) also worked together on Happy Valley (2014) as Frances Drummond & Sean Balmforth respectively.

Brendan Gleeson has worked with two other Dumbledores. His first film was The Field (1990) with Richard Harris. He also appeared in A.I. Artificial Intelligence (2001) and Cold Mountain (2003) with Jude Law.

Throughout the eight-movie series, five actresses played Pansy Parkinson: 1-Katherine Nicholson [Harry Potter and the Sorcerer's Stone (2001), and Harry Potter and the Chamber of Secrets (2002), uncredited in both], 2-Genevieve Gaunt [Harry Potter and the Prisoner of Azkaban (2004)], 3-Charlotte Ritchie [Harry Potter and the Goblet of Fire (2005), originally listed as "Student" and uncredited)], 4-Lauren Shotton [Harry Potter and the Order of the Phoenix (2007) (again uncredited as Pansy], and 5-Scarlett Byrne in Harry Potter and the Half-Blood Prince (2009), Harry Potter and the Deathly Hallows: Part 1 (2010), and Harry Potter and the Deathly Hallows: Part 2 (2011).

At the beginning of the movie, the caretaker is listening to the radio and it gives the forecast in degrees Fahrenheit. Taking place in England, the temperature should be given in Celsius.

When Chris Columbus scripted Young Sherlock Holmes (1985), Watson believed Holmes obsessed over a case, even at Christmas, because unlike other boys his age, he had no family to which to go home, like Harry Potter or Kevin McCallister. Columbus has ties to both the Harry Potter and Home Alone franchises.

Even though Barty Crouch junior as Mad Eye Moody introduces the three unforgivable curses Voldermort at the start of the film was the very first character to use the killing curse in this case on Frank Bryce unless one considers the flashback of Lily Potter being killed in the Philosopher's Stone. However the other two curses were mentioned for the first time by Crouch Junior.

Victor Krum and his fellow Drumstrang students wear red during the Yule ball. Red is of course one of the colors of Gryffindor.

Mike Newell: The voice heard on Frank Bryce's radio in the beginning of the film.

Stanislav Yanevski, who plays Viktor Krum, has only two lines, totalling twenty words, in the entire film.

The occasional tongue flick done by the character of Barty Crouch, Jr. was, in fact, not in the book at all, and was improvised, on the spot, by David Tennant. Brendan Gleeson then added the quirk to a few of his scenes as a hint to the Crouch/Moody substitution. In fact, after the second task, when "Moody" and Crouch, Sr. are talking, Crouch's reaction to seeing Moody do this, could suggest that he might know something about Moody's true identity.

Robert Pattinson has stated that he would much rather play Cedric Diggory again, despite the character being killed off in this film, than play Edward Cullen in the Twilight Saga, the role he is perhaps best known for.

Ralph Fiennes was not wearing any make up to cover his nose. In order to make the character scarier, film editors digitally removed it. Also, the "red, snake-like eyes" the novel describes were not added, due to the actor's thought that the expression in his eyes would provide a better idea of Lord Voldemort's insanity and malignity.

(at around 2h) Voldemort identifies four of his Death Eaters by name: MacNair, Crabbe, Goyle, and Lucius Malfoy. Lucius Malfoy is the father of Draco Malfoy. The Crabbe and Goyle that he names are the fathers of Draco's friends, who are also usually addressed by their last names. The last one, MacNair, is identified in the book as the would-be executioner of Buckbeak in Harry Potter and the Prisoner of Azkaban (2004).

(at around 1h 45 mins) In the film it is stated that Barty Crouch, Jr. performed the Cruciatus Curse (torture curse) on Frank and Alice Longbottom, however in Harry Potter and the Order of the Phoenix (2007), Neville Longbottom states that his parents were tortured by Bellatrix Lestrange. In fact, both are correct. The books state that the Longbottoms were tortured by a group of Death Eaters, including Barty Crouch, Jr. and Bellatrix and Rodolphus Lestrange. Dumbledore adds that, while the Lestranges were sadistic by nature, Crouch Jr. was very young, and easily swayed, and probably coaxed into doing it by the others.

There were four characters that had big parts in the book, but were completely written out of the film. These characters were: Ludo Bagman, head of the Ministry of Magic's sports department and tournament judge; Winky: the former Crouch house elf that was believed to have cast the dark mark at the Qudditch World Cup; Bertha Jorkins: a woman who was tortured by Voldemort and Wormtail to tell them about the Tournament being held at Hogwarts; and Bellatrix Lestrange, one of Voldemort's fiercest supporters, as seen in Dumbledore's Pensieve memory. Lestrange would finally be introduced in the next film, Harry Potter and the Order of the Phoenix (2007).

The writing out of Dobby in this film (Harry Potter and the Order of the Phoenix (2007)) resulted in a slightly larger role for Neville Longbottom. In this film, it is Neville, rather than Dobby, who gives Harry the gillyweed for the second task, and we later learn that this idea was given to him by Barty Crouch, Jr./Professor Moody. In the book, Crouch/Moody explains that his first approach was in fact to give Neville the book where gillyweed could be found, but Harry didn't ask Neville, because he wasn't supposed to ask for help, so he only told Ron and Hermione what he had to do. So Moody arranged for Dobby to overhear him talking about it. This removal creates a rather uncharacteristic byproduct - Neville, who is supposed to be terrified of Professor Snape, would have had to steal the Gillyweed from Snape's store.

(at around 6 mins) At the Quidditch World Cup, Amos Diggory says "Parting of the ways?" to Arthur Weasley, and they separate to go to their respective tents. This is a line from the book, only in different context. In the book, Dumbledore says this to Cornelius Fudge, when Fudge refuses to admit that Voldemort has returned. For pacing reasons, this epilogue was deleted from the movie, in favor of using it as a subplot for Harry Potter and the Order of the Phoenix (2007).

(at around 1h 45 mins) When Harry was talking to Dumbledore in his office, after seeing the flashback of Barty Crouch, Jr., you can see the Deathly Hallows symbol when Dumbledore looks into the glass cabinet.

(at around 37 mins) You can clearly see the Elder Wand for at least fifteen seconds, when Dumbledore takes his memory to the Pensieve. The Elder Wand is the vital element in the last installment, Harry Potter and the Deathly Hallows: Part 2 (2011).

In the book, while Harry is in the maze, he faces a sphinx, and has to solve the sphinx's riddle, but in the movie, there is no sphinx.

(at around 23 mins) It could be implied Karkaroff was the person who put Harry's name in the Goblet of Fire, as he is seen entering the Great Hall where the goblet is, before giving a very shifty looking appearance, before closing the door, just before Moody's lesson about the Unforgivable Curses. Plus, Karkaroff gives another shifty look when the goblet is about to spit out Harry's name. This suggests that even though Harry claimed Moody (who is really Barty Crouch, Jr. in disguise) put his name in. Karkaroff was either aiding Crouch, Jr. to bring back Voldermort, or more likely, was placed under the Imperius Curse by Crouch, Jr.

When Barty Crouch Jr. is in disguise as Mad Eye Moody his tick with his tongue is on the opposite side as to Barty Jr. David Tennant (Barty) displays his tick at the right corner of his mouth whereas Brendan Gleeson (Moody but in disguise) displays it on the left side of his mouth.

This was the second time in 2005 that another actor changed into David Tennant, the first being Doctor Who (2005), where Christopher Eccleston regenerated into Tennant. In this, Brendan Gleeson changes into Tennant after the Polyjuice potion wears off.

When the twins are denied entering their names in the Goblet of Fire, they are thrown out and grow beards. When they start wrestling, Fred tells George, "Get off or I'll tear your ears off." In Part one of the Deathly Hallows, George gets his ear cursed off by Snape.

Whereas in the book, what happens to Fleur while she's in the maze is unknown, in here it's shown (Though this likely didn't happen in the book) that after she stays next to an enchanted hedge for too long after being stunned by Krum, it reacts by grabbing her and tying her up with its roots and pulling her under it. Incapacitated, she does nothing to try to resist it or get away from it. Harry hears her scream and attempts to come to her aid, but by the time he reaches her (He is unable to find her in the book) she's already been pulled so close to it that he was unable to save her, so he sent red sparks in the air so that one of the teachers patrolling the maze would rescue her.

Emma Watson wearing a lilac dress in the film is similar to the dress Hermione Granger wore at Bill and Fleur's wedding in the book version of Harry Potter and the Deathly Hallows in description.