Pierce Brosnan had no idea what the project was about when he signed on. The producers told him it was being filmed in Greece, and Meryl Streep was starring. Brosnan said he would've signed on for anything involving Streep, describing her as "that gorgeous blonde I fancied terribly in Drama School."
Meryl Streep first saw the musical in October 2001 with her daughter Louisa, and her daughter's friends in Manhattan. Streep wrote to the producers to praise them for bringing a little happiness and fun to the lives of New York City's people following the 9/11 terrorist attacks.
Meryl Streep went to Stockholm, Sweden to record her vocal for the song "The Winner Takes it All". She finished it in one take. Benny Andersson, former ABBA member and co-composer of the songs, called Streep "a miracle".
The cast members performed their own singing.
Colin Firth once stated that if Heaven exists, when he arrives he wants to hear God say "I personally thought you were very good in Mamma Mia"
Björn Ulvaeus: Composer and executive producer is dressed as a Greek god during the closing credits sequence.
Rita Wilson: The executive producer is dressed as a Greek goddess during the closing credits sequence.