Continuity mistake: When Sophie is finally dressed for her wedding, the gauzey material is predominately over her right shoulder/breast. Next shot it is over her left. When she gets on the donkey, it is completely off her right side and her bra shows.

Mamma Mia! (2008)
Trailers
Directed by: Phyllida Lloyd
Starring: Meryl Streep, Pierce Brosnan, Colin Firth, Amanda Seyfried, Stellan Skarsgard, Julie Walters, Christine Baranski





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.