Trivia: All of the entire cast performed their own singing.
Trivia: While neither the stage show nor the film reveals who Sophie's real father is, there is an official answer. According to Catherine Johnson and Phyllida Lloyd, Sophie's real father is Bill. Bill's character was Australian in the original stage production, but in the film he became a Swede instead, and he's played by Swedish actor Stellan Skarsgård. This means the film's Sophie has her roots in Sweden - just like "Mamma Mia!"
Trivia: Rosie's cookbook that is mentioned in the beginning of the movie is a bit of an inside joke and refers to "Calendar Girls" that Julie Walters starred in.
Answer: Sophie finds Donna's diary from 1979, being the year Sophie was conceived meaning she was born in 1980 (as the diary entries are from July/August). So the movie is set in 2000.