Pierce BrosnanMeryl StreepAmanda Seyfried Mamma Mia, here we go again! A sequel to the ABBA-packed film musical "Mamma Mia!" will hit theaters on July 20, 2018. will see the return of the film's original cast and feature a soundtrack of ABBA songs not included in the first. The 2008 film starred Meryl Streep, Amanda Seyfried, Pierce Brosnan and Colin Firth and was a smash global hit, earning over $609 million worldwide. Talks of a sequel have circled for years.