Just as Stephen Amell (for the title role of Arrow (2012)) and Grant Gustin (for The Flash (2014)), Melissa Benoist was the very first of a thousand actors to audition for the role of Supergirl.

Tyler Hoechlin (Clark Kent/Superman) went to prom with Katie Cassidy who portrays DC Comics character Laurel Lance/Black Canary/Black Siren in Arrow (2012) and The Flash (2014).

The Supergirl costume was designed by Colleen Atwood, who also designed the costumes for Arrow (2012) and The Flash (2014). She had previously designed the Superman outfits that would be used in the failed film "Superman Lives" which would star Nicolas Cage in the title role.

In Supergirl: Myriad (2016), Cat Grant says to tell "Harrison Ford she is flattered but she does not date older men, especially when they're married." Calista Flockhart, who plays Cat Grant, is 22 years younger than her husband Harrison Ford.

Reunites Helen Slater, who played the title character in Supergirl (1984), and Dean Cain, who portrayed Superman in Lois & Clark: The New Adventures of Superman (1993). Both also have previously appeared in Smallville (2001), where Laura Vandervoort portrayed Kara Zor-El/Supergirl. Additionally, Teri Hatcher, who portrayed Mon-El's mother Queen Rhea, played Lois Lane in Lois & Clark: The New Adventures of Superman (1993) and later Ella Lane in Smallville (2001).

The sound effect used in Supergirl for her X-ray vision is the same one used in Smallville (2001).

Kara keeps her name and assumes the surname Danvers after she is adopted. In the comics, however, Kara assumed the full name of "Linda Lee Danvers" after she was adopted.

In late 2014, various reports suggested that this project, planned for CBS, could tie into the shared universe of two other hit superhero shows, Arrow (2012) and The Flash (2014), which air on The CW but are also co-owned by CBS. This was later confirmed, when it was announced in February 2016 that Grant Gustin from The Flash would be appearing in a crossover episode as his character. Later still, in 2016, reports were made of the show moving "properly" to CW for season 2, with further crossovers to be expected.

In an early episode, it is mentioned that Metropolis was destroyed during one of Superman's fights as a nod to Man of Steel (2013). A comic book prequel for that film revealed that Kara Zor-El does exist in that universe.

In addition to acting, Melissa Benoist, Chris Wood, Jeremy Jordan, Chyler Leigh, Mehcad Brooks, David Harewood and Laura Benanti all can sing. According to Melissa Benoist, the idea of a musical episode became "a kind of a running joke" among the cast due to this. A crossover musical event was announced in 2016 between this show and The Flash (2014), starred by Grant Gustin who is also a singer. Melissa and Grant have both appeared on Glee.

Blake Jenner, who's portraying Adam Foster (Cat Grant's son and Kara's love interest) in the series, is married to the actress that portrays Kara Zor-El, Melissa Benoist. (Benoist has filed for divorce in December 2016)

Tyler Hoechlin was cast without auditioning for the role of Clark Kent/Superman.

The project went through a long and intensive casting process in order to find an actress to play the title character. In January 2015, it was announced that Melissa Benoist had been cast as the lead. Benoist had long been considered a favorite for the role. Other actresses who were considered include Claire Holt, Gemma Atkinson and Elizabeth Lail.

Helen Slater (who starred as Kara Zor-El in Supergirl (1984)) also portrayed Kal-El's birth mother Lara in Smallville (2001). She now appears as Kara's adoptive mother Eliza Danvers.

Melissa Benoist dyed her natural brunette hair blond before she was cast, and reportedly when she was not really expecting to get the part.

Ironically, DC Comics canceled the Supergirl comic book title close to this series' premiere in 2015. It was announced the following year that it would return as part of the "DC: Rebirth" event (as "Supergirl: Rebirth"), incorporating many elements from this series such as the costume, Supergirl working with the D.E.O., the civilian identity of Kara Danvers, original characters Jeremiah and Eliza Danvers and National City. The comic was then canceled again in February 2018.

Melissa Benoist is the second Glee (2009) cast member to star as a DC comics superhero. Grant Gustin portrays the title character in The Flash (2014).

Laura Benanti, who's portraying Alura Zor-El in the series, is 9 years older than her TV daughter Melissa Benoist, and Erica Durance, who replaced Benanti, is 10 years older than Benoist.

Melissa Benoist read the New 52 "Supergirl" comic in preparation for her role, and reportedly some of them were used in her audition. She was then told by the producers that the TV series would go in a different direction.

Kara and Siobhan Smythe/Silver Banshee become enemies from the moment they meet in this series, while in the "New 52" continuity, they become best friends and later roommates. Siobhan turns out to be the only being on Earth able to understand Kara's Kryptonian speaking due to her Silver Banshee nature, and the first to recognize her as a hero.

Chyler Leigh is eight years older (34 years old) than her character (26) in this series. In contrast, 28-year-old Tyler Hoechlin portrays the 36-year-old Superman.

Initially, while Superman does make brief appearances (played by an uncredited Kevin Caliber) his face is always obscured or off-screen and his voice not heard, with Kal-El only appearing as a child, and the guise of Clark Kent never seen at all (but still communicating with Kara, via text messages). Then, with the show's move from CBS to CW after the first season, it was announced that a 'proper' outing of the character would follow in subsequent seasons with Tyler Hoechlin in the role.

The universe this series is set is designated as Earth-38 as a reference to the year "Action Comics" #1, Superman's first appearance, was published, 1938. In the comics, Earth-38 is a world wherein the heroes (Batman, Superman, Wonder Woman, etc) appeared early in the 30s and aged normally, passing on their legacies to their respective descendants.

In the comic books, Mon-El has the same powers as the modern era Supergirl and other Kryptonians, however here his abilities are considerably reduced and resemble the original power level of Superman when the latter was created in 1938. This includes comparatively weaker super strength, an inability to fly, and no super senses.

Melissa Benoist had an eye injury and wore an eye-patch when she put on the Supergirl outfit for the very first time, describing her look as "kind of embarrassing".

The series makes occasional indirect references to Batman, including the mentioning of Gotham City, and Kara, James and Winn talking about a scary masked vigilante "with a lot of gadgets and a lot of issues" that works with Superman.

Andrew Kreisberg confirmed on Twitter that Kara's ears were pierced when she was still on Krypton. For a brief second, it is possible to see that young Kara's ears are pierced indeed, when she is in her pod.

The character of Maxwell Lord (Peter Facinelli) was killed by Wonder Woman in the comics. Eventually he was resurrected in the crossover limited-series "The Brightest Day".

According to Brandon Routh on Twitter, the "bulletproof coffee" Cat mentions in the third episode was used by writer Andrew Kreisberg after Routh's "obsessive" use of the term. Routh, of course, played the title character in Superman Returns (2006) and stars as The Atom in Arrow (2012) and its spin-offs.

Briana Venskus who portrays Agent Vasquez in the first season also appeared as Agent Piper on Agents of S.H.I.E.L.D. (2013) as part of the Marvel Cinematic Universe.

Colleen Atwood designed the House of El coat of arms to be looked at "in flight". Melissa Benoist laid on a table during costume tests "to make sure that it looks good horizontally".

To reduce costs, filming has changed from Los Angeles to Vancouver, as the series itself has moved from CBS to The CW alongside Arrow (2012), The Flash (2014) and Legends of Tomorrow (2016).

According to Melissa Benoist, Chyler Leigh and herself think the character of Alex Danvers could make a "really good" Batgirl.

Several episodes make allusions and references to another DC comics property, "The Legion of Superheroes". These includes the appearance of a Legion flight ring in the Fortress of Solitude, the mentioning of various alien races and planets that figure prominently in the Legion storylines, the introduction of Mon-El, and the name-dropping of that character's alternate identities, "Lar Gand" and "Valor (Val-Or)". The Legion are a teenage superhero team founded in the 31st century that was inspired by the exploits of Superboy. Through various types of time travel, Supergirl, Superman, and Mon-El all became members of the Legion.

Reunites Dean Cain and Teri Hatcher, who starred as the title characters in Lois & Clark: The New Adventures of Superman (1993).

Melissa Benoist (Kara Danvers / Supergirl) is the only actor to appear in every episode of the series.

The Midvale High School scenes are filmed at the Vancouver Tech School, the same building used as Smallville High School in Smallville (2001).

Brenda Strong portrays Lillian Luthor; Strong is best known for playing Sue Ellen Mischke on Seinfeld (1989). On that series Jerry refers to Sue Ellen as Elaine's "Lex Luthor", referring to them being arch enemies. Lillian is Lex Luthor's mother on "Supergirl".

Katie McGrath suggested Bruce Willis for the role of Lex Luthor.

It took 4 hours to apply Roulette's snake tattoos on Dichen Lachman.

Erica Durance replaced Laura Benanti as Alura Zor-El in Season 3 after Benanti was unable to continue in the role due to work commitments in NY. Durance starred as Lois Lane in Smallville (2001).

In May of 2015, a source of the entire pilot episode was leaked on the internet, 2 weeks after the first trailer was released, and 6 months before the show's premiere.

The series takes place in National City (a fictional community). DC Comics, from which Supergirl is a character, was previously known as "National Comics" (amongst other company names).

Tyler Hoechlin appeared on Teen Wolf (2011) alongside Dylan Sprayberry, who portrayed the young Clark Kent on Man of Steel (2013). Furthermore, "Teen Wolf" stars Tyler Posey and Ryan Kelley appeared in episodes of Smallville (2001).

Tyler Hoechlin reportedly felt difficult to suit up as Superman. "I started to think that Superman's greatest power was actually being able to just jump into [the suit] as quickly as he does, because it's not quite as smooth the first couple of times you do it."

For the exterior shots of Lord Technologies headquarters, a shot of Berlin/Germany's Central Station with a mounted Lord logo is used.

Cat repeatedly addresses Kara as "Kyra." Kara stopped trying to correct her after the second episode.

Prior to being cast as Clark Kent/Superman, Tyler Hoechlin was considered to portray Bruce Wayne/Batman in Batman v Superman: Dawn of Justice (2016), but that role ultimately went to Ben Affleck.

David Harewood publicly expressed dissatisfaction in playing Hank Henshaw/Cyborg Superman. He felt the writers gave the character no depth.

The neon pink statue of the cat sitting in the foyer near Cat Grant's office is the exact same model of the two cats that perch at the top of the clock tower in the Back to the Future (1985) trilogy.

Greg Berlanti has described Melissa Benoist as the Annie Hall (1977) of superheroes.

Melissa Benoist cited Susan Sontag and Gloria Steinem as inspirations for her portrayal of Supergirl. A feminist, Steinem was notably a huge fan of Wonder Woman.

The "alien code" that Wynn is attempting to read in the episode 'Solitude' is the Kryptonian language used in Smallville (2001), the only difference being the characters scroll top to bottom/bottom to top instead of left to right/right to left.

While National City was originally created for the show, it first made its appearance in the comics with Action Comics #51 of the Action Comics New 52 series (after being first mentioned in Batman/Superman #31) when a dying Superman (New 52 version) tracked down Supergirl and found her at the D.E.O. and mistakenly thought she was being held prisoner. National City would be officially shown as Supergirl's home starting with the relaunch of the Supergirl comic book series in the DC Rebirth event not long after.

Melissa Benoist (Kara Danvers/Kara Zor-El/Supergirl), Peter Facinelli (Maxwell Lord), and Blake Jenner (Adam Foster) all worked on Glee (2009).

Kevin Smith's episode is titled "Supergirl Lives", after "Superman Lives", the infamous movie he wrote, which would star Nicolas Cage in the title role (See The Death of "Superman Lives": What Happened? (2015).) Smith joked he wanted Supergirl to fight a giant spider, referencing the infamous battle scene proposed for that film.

Kara's foster parents are named Jeremiah and Eliza Danvers, a change from the previous comics in which the Danvers first names were Fred and Edna. In Peter David's run, Linda's parents were Fred and Sylvia Danvers. However, when the 2016 Supergirl comics were released as part of DC Rebirth, Kara's foster parents were given the same names as the ones in the show as that series would adapt a number of elements from the TV series.

Lynda Carter has admitted that she based her performance as President Olivia Marsdin on Hillary Clinton.

Plastino Chemicals and the Otto Binder Bridge in National City are, of course, references to Otto Binder and Al Plastino, co-creators of Kara Zor-El/Supergirl. However, only Superman creators Jerry Siegel and Joe Shuster are credited.

This is the second time Chyler Leigh has played a character with a name that derives from "Alexander." On Grey's Anatomy (2005) she played Alexandra ""Lexie" Caroline Grey and on Supergirl (2015) she plays Alex Danvers.

When a picture of Laura Vandervoort from V (2009) was used to make fake ID passports as part of an international identity-theft ring, she was immediately recognized by an FBI agent who happens to be a fan of Smallville (2001) wherein she portrayed Kara Zor-El/Supergirl.

As a guest on Ellen: The Ellen DeGeneres Show (2003), Melissa Benoist received from Ellen DeGeneres Superman-themed costumes for each of her dogs. One of them is named Otis, same name of Lex Luthor's assistant in the Superman (1978) films.

Presidential candidate Jeb Bush made headlines after commenting Melissa Benoist "looked pretty hot" in a TV promo for this series premiere.

Alex Danvers does not exist in the comics and was created for the series. She notably resembles Linda Danvers/Supergirl, the character created by Peter David after Kara Zor-El was wiped out of comic book continuity.

Jeremy Jordan, who plays Winn, was born on November 20, 1984, just one day before the theatrical release of Supergirl (1984).

Creator and producer Andrew Kreisberg described this version of Superman as being in a "bit more traditional way", with bits of Christopher Reeve's portrayal and the versions from Superman (1996), Lois & Clark: The New Adventures of Superman (1993) and Super Friends (1973).

Italia Ricci (Siobhan Smythe) is married to Robbie Amell who portrays Firestorm in The Flash (2014).

Glenn Morshower, General Sam Lane, had a role in X-Men: First Class (2011) with Michael Ironside, who played General Lane in Smallville (2001).

In separate episodes, Melissa Benoist, Mehcad Brooks, and Jeremy Jordan have all appeared on Law & Order: Special Victims Unit (1999). After leaving the series in 2011, leading man Christopher Meloni had a supporting role in the Superman reboot Man of Steel (2013).

The fiftieth episode happens to be the crossover event Supergirl: Crisis on Earth-X, Part 1 (2017) in which Melissa Benoist portrays both Supergirl and Overgirl, her evil, Nazi counterpart from Earth X.

Winn Schott is one of two Arrowverse characters that have become the Dollmaker in the comics. The other is Barthon Mathis, portrayed by Michael Eklund in Arrow (2012). However, in the comics, the Toyman's son is named Anton Schott.

Jay Jackson appears as a newsreader in the show. He is known for playing the newsreader and reporter Perd Hapley in Parks and Recreation (2009).

The fact that Hank Henshaw is African-American in the show, unlike the comics, as well the design of the cybernetic implants he has on his face, including the faceplate he wore over his cybernetic eye in the episode "Medusa" gives him a closer resemblance to Victor Stone, aka the superhero Cyborg, than his original comic book counterpart.

One of two concurrent television dramas based on Superman comics on air as of 2018, the other being Krypton (2018).

Supergirl battled four Worldkillers in the comics: Reign, Deimax, Flower of Heaven and Perrilus. In this series, they are Reign, Purity and Pestilence who, like Perrilus, has the abilities of poison generation and virus dissemination.

The first superhero television drama to feature a transgender superhero played by a transgender actor.

Features the characters of Non (Chris Vance) and Eve Teschmacher (Andrea Brooks) which were created by screenwriter Mario Puzo for Superman (1978), famously portrayed by Jack O'Halloran and Valerie Perrine respectively. The witch Selena is a character created for the Supergirl (1984), played by Faye Dunaway.

Dean Cain who portrayed Jeremiah Danvers also played the character with same last name of Danvers in Vendetta (2015) as Mason Danvers.

Much for production designer's Seth Reed's "heartbreak", the Fortress of Solitude set used in the first season was torn down after production moved from Los Angeles do Vancouver. Reed explained that "it's heartbreaking because you put a lot of care into something and it's all for the sake of capturing it on film".

Sarah Douglas guest stars in one episode. She lobbied for a Smallville (2001) appearance for years like other Superman (1978) actors but was never invited.

The series' starting point is loosely inspired by the 2010 Sterling Gates-Jamal Igle comic run which had Kara assuming the identity of Linda Lang (with a nerdy, Clark Kent-like attire), developing a sister-like relationship with Lana (Alex), and had Cat Grant as a recurring character. In the same arc, Supergirl and Cat confronted the Dollmaker, a villain revealed to be Anton Schott, the estranged son of the Toyman (Winn).

The opening credits state that the series is "based on characters created by Jerry Siegel and Joe Shuster." However, neither of Superman's creators had any involvement with the creation of Supergirl, who made her first appearance in Action Comics #252 (May 1959). The creators of Supergirl were Otto Binder and Al Plastino. Other than Superman himself, the only character created by Siegel and Shuster to appear in the series is James Olsen.

Melissa Benoist is a natural brunette. In the first season, Kara is depicted in a darker hair tone in comparison to her blonde hair in the comics. However, it appears brighter each season.

Throughout the series, Supergirl and Superman are depicted as being somewhat paranoid about kryptonite, with Superman refusing to work with the DEO until they turn over their supply of the substance, and Supergirl being personally offended that Lena Luthor has a supply and can also synthesize it. This attitude is not consistently kept, however, as Oliver Queen and Alex Danvers are both shown using kryptonite weapons, supposedly after Superman confiscated all the kryptonite. Neither is ostracized or confronted for doing so.

Carl Lumbly guest stars as J'onn J'onzz/Martian Manhunter's father M'Yrnn J'onzz. He starred as the Martian Manhunter himself in Justice League (2001). In the comics, M'Yrnn was killed by J'onn's evil twin brother Ma'alefa'ak/Malefic.

Season three introduces a noticeable change in the show's main musical theme, both at the start and end, where the brass melody has been more or less removed from the music.

Creator Dan Jurgens spoke against the changes made on Benjamin Lockwood/Agent Liberty in this series. In the comics, the character was a hero rather than the villain depicted in the show.

Jesse Rath reportedly "stole" the Legion Ring from the Art Department to use it at the "Supergirl" 2018 San Diego Comic-Con panel.

As revealed by Chyler Leigh at the ClexaCon in Las Vegas, many "Sanvers" scenes were filmed but never aired.

If was announced at San Diego Comic Con in July 2018'that they would introduce first transgender superhero next season. Transgender actor Nicole Maines has been cast as Nia Nal, who will come to the fictional National City in the show's fourth season and receive guidance and training from the title character.

Winn thinks Kara is a lesbian when she is about to reveal her secret identity as Supergirl. In the comics, the Danvers had the same conclusion before their daughter Linda "comes out" as Supergirl to them.

Laura Vandervoort portrays Indigo, a DC Comics character later revealed to be Brainiac 8. In Smallville (2001), Vandervoort, portraying Kara Kent was possessed by Brainiac.

In the comics, the character of Lucy Lane assumed the alter ego of Superwoman (who had a costume bearing a field that simulated Kryptonian powers), and was eventually confronted by Supergirl in the story arc "Who Is Superwoman?". Lucy is one of several characters to take the Superwoman mantle, along with Kristin Wells, Lana Lang and Lois herself.

When David Harewood was told that he was actually playing Martian Manhunter, he reportedly thought "I'm going to be playing Shrek (2001) for the next seven years".

The Martian Manhunter is friends with Jeremiah Danvers and is granted the mission to protect his daughters Kara and Alex. In Smallville (2001), the opposite happens: the Martian Manhunter is friends with Jor-El and is granted the mission to protect his son Kal-El/Clark on Earth.

The character of Mon-El, introduced in the second season, was originally a mysterious space explorer that crash landed on Earth without his memories Since he had kryptonian abilities and was found on a Monday, Superboy dubbed him Mon-El. It was later discovered that Mon-El had a hyper-sensitivity to lead poisoning, and after a fatal exposure, Superboy was forced to exiled his friend to the Phantom Zone to save his life. 1000 years later, the Legion of Superheroes were able to release Mon-El and cure his lead poisoning, and he was reunited with Superboy and Supergirl when they time-traveled to the future and joined the Legion. In the comics, Mon El's real name is Lar Gand, and he does not have a romantic relationship with Supergirl. Rather, the Legion member who saved him, Brainiac 5, is Supergirl's love interest.

The main story arc in season 1 has Kara accidentally releasing Phantom Zone prisoners which she then has to track down. The same story arc features in season six of Smallville (2001).

Chyler Leigh portrayed Dr. Lexie Grey (sister of the title character) who died after an airplane crash in Grey's Anatomy (2005). In this series, she is again the sister of a title character, and is saved by her from perishing in an airplane crash in the Pilot.

Martian Manhunter's human disguise is Hank Henshaw. In the comics, Hank Henshaw is the name belonging to Cyborg Superman, one of the four Supermen to appear after Superman fell in battle with Doomsday.

Live action debut of several DC Comics characters such as Doctor T.O. Morrow, the White Martians, Miss Martian, Hellgrammite, Red Tornado, Dream Girl, Agent Liberty, James Harper, Mon-El, Draaga, Psi, Reign, the Guardian, Cameron Chase, Indigo/Brainiac 8 and the Bizarro Supergirl.

Lex and Lena Luthor's mother is Lillian Luthor, a name that was conceived for Smallville (2001). In the comics she was originally named Arlene Luthor, later renamed Letitia Luthor. Lex mentions an aunt named Lillian in "Superwoman" #6.

In this series, James (Jimmy) Olsen assumes the mantle of the Guardian, a Golden Age vigilante created by Jack Kirby and Joe Simon, also the creators of Marvel's Captain America. In the comics, James Harper is the original Guardian, and does appear in this series as well, in his live-action debut.

Odette Annable originally auditioned for the role of Alex Danvers. She was later cast as Samantha Arias/Reign in the third season.

Several aspects of the Superman mythos featured in this series are taken directly from Smallville (2001) such as the Red Kryptonite effect on Kryptonians, Clark and Lex growing up as friends before taking on different sides, Lena Luthor being born from an affair of Lionel Luthor, the Luthor family itself and the original character of Chloe Sullivan.

Cat Grant is a mother of two in this series. In the comics, she had a young son who was accidentally killed by Winslow Schott, the Toyman.

In the comics, the character of Maggie Sawyer goes in a romantic relationship with Batwoman. The characters were supposed to marry each other but DC vetoed this idea.

The Martian Manhunter is an ally of Supergirl in this series. In the comics, the Supergirl known as Matrix, a character created to replace Kara Zor-El, had powers similar to his - shape-shifting, telepathy and telekinesis.

Cat Grant becomes the White House Press Secretary in the third season. In the comics, she worked as President Lex Luthor's Press Secretary until Lex was impeached.

Supergirl's Earth-X counterpart Overgirl is killed by overexposure to solar radiation. This is taken from the acclaimed "All-Star Superman" series, wherein Superman's cells are overwhelmed with solar radiation, leaving him with one year left to live.

It is revealed in the third season that Argo City survived Krypton's destruction. In the comics, Kara is originally born and raised on Argo City (after Krypton's explosion) from where she was sent to Earth. Subsequent reboots have Kara being sent from Krypton along with Kal-El as depicted in this series.

Guest star Erica Durance portrays FBI agent Noel Neill, a reference to actress Noel Neill who starred as Lois Lane in Adventures of Superman (1952). Durance herself starred as Lois in Smallville (2001).

This series' take on the DC villain Reign is strongly similar to Doomsday's storyline in Smallville (2001): both live on Earth as ordinary, benevolent humans until they discover their true evil nature as beings sent to Earth alongside Kal-El and Kara Zor-El to destroy it. Furthermore, Sam Witwer who played Davis Bloome/Doomsday also guest stars.

The series deepens Supergirl and Mon-El's romance which was a mere flirt in the comics. Querl-Dox/Brainiac 5 is one of Supergirl's longest relationships in the DC Comics universe.

This series marks the live-action debut of Lex Luthor's trademark warsuit which his mother Lillian dons.

The heroic costume Alura Zor-El dons at the end of the third season was designed referencing one the character is seen in during the "New Krypton" saga in the comics.

In episode 12 of season 3 Alex mentions to Samantha that she was a doctor at a hospital in Seattle and was going into research. In Grey's Anatomy Chyler Leigh protrayed Lexie a doctor who worked at fictional Seattle Grace Hospital in Seattle Washington.