Had the biggest opening weekend at the box office in the careers of Meryl Streep, Amanda Seyfried and Cher.
Meryl Streep and Lily James, the two actresses portraying Donna, are distant relatives - ninth cousins, three times removed to be precise.
Cher handpicked Andy Garcia to play the character of Fernando out of a bunch of selected actors.
Julie Walters was given a day off from the Shepperton Studios filming in November 2017 (during the taping of the "Angel Eyes" number) so she could attend an investiture ceremony at Buckingham Palace, where she was made a Dame Commander of the Order of the British Empire by Queen Elizabeth II. The cast and crew garnered to surprise and welcome Walters back while singing "There Is Nothing Like a Dame" from the South Pacific musical.
Amanda Seyfried was told by her agent that the film had been officially green-light, exactly on the day she came home from the hospital, after giving birth to her daughter.
When young Donna and the group leave the graduation, they end up on the dock where a small boat is shown with the name Chiquitita (an ABBA song used in the 1st film).
Cher is just three years older than Meryl Streep, despite them playing mother and daughter.
After appearing in this film, Cher decided to make a full album of ABBA covers, aptly titled "Dancing Queen".
The musical score played during the film is a mostly comprised of songs featured in the first film and unused ABBA songs.
Despite being an actress for over 40 years, this film marks the first time in her career that Meryl Streep has ever done a sequel.
The first time Julie Walters met Cher, she ran up to her in a rush of excitement and gave her a warm hug. However, Walters' glasses got stuck in Cher's white wig, leaving it tarnished, and a new wig had to be used for filming.
Cher was originally offered the role of Tanya in the first film which she turned down. She appears in this movie but in a different role, per invitation of her former agent and dear friend, Ron Meyer, who is now head of Universal Studios.
The trailer sets Donna (Meryl Streep)'s pregnancy in 1979, and the birth of Sophie as 1980, which sets Mamma Mia! (2008) around 2000, as Sophie is 20. The movie is set 5 years after the first film, which would make this 2005.
The film choreographer is the same choreographer who worked with the traveling Mamma Mia North American Farewell Tour.
Stellan Skarsgård, Jeremy Irvine and Colin Firth also co-starred together in The Railway Man (2013), where Irvine played the younger version of Firth's character. In Mamma Mia! Here We Go Again, Irvine plays the younger version of Pierce Brosnan's character.
Hugh Skinner (Young Harry) and Amanda Seyfried (Sophie) both appeared in the 2012 film Les Misérables (2012) with Skinner playing Joly and Seyfried playing Cosette.
Lily James and Stellan Skarsgård also appeared in the live action version of Disney's Cinderella. James played Cinderella and Skarsgård played the Grand Duke.
Cher, who is playing Sophie (Amanda Seyfried)'s grandmother in this movie, had a cameo in ABBA's last video in 2004, named ABBA: Our Last Video Ever (2004). The video was released due to ABBA's 30th anniversary since the winning of the Eurovision Song Contest 1974 (1974). In the video, Cher was an audience member while ABBA, portrayed by puppets, performer their winning song "Waterloo."
This film marks the second film collaboration between Cher and Meryl Streep, the first being Silkwood (1983). They were also in Stuck on You (2003) together where Meryl Streep made an uncredited appearance in the movie.
When young Donna (Lily James) walks with young Harry (Hugh Skinner) in Paris by the fountain, he is wearing a Johnny Rotten t-shirt. This is referenced by Colin Firth in the first film before he sings 'Our Last Summer' when he refers to buying his guitar for "ten quid plus this Johnny Rotten t-shirt".
In the first film "Mamma Mia!" Donna (Meryl Streep) has blue eyes. Whilst in this film "Mamma Mia! Here we go again" Donna (Lily James) has brown eyes.
There's a reference to the Beatles early on in the movie when Sophie is addressing the invitations for the party she is planning. One of the addresses is c/o Epstein Martin, a composite of the surnames of the Beatles manager Brian Epstein and their record producer George Martin.
Celia Imrie and Julia Walters previously appeared together in Dinnerladies (1998) and Calendar Girls (2003)
Josh Dylan (Young Bill) and Jeremy Irvine (Young Sam) had to wear hair pieces for their roles as they had short hair cuts at the time of filming. Christine Baranski also wore a brown wig while filming the movie.
Björn Ulvaeus: The ABBA member makes a cameo appearance in the number "When I Kissed the Teacher" as a college chancellor.