Movie Preview: Full-Length Trailer for Mamma Mia! Way back in December we got our first glimpse at Mamma Mia!, which stars Meryl Streep, Pierce Brosnan, Amanda Seyfried and Colin Firth, with a teaser. Now, there's a full-length trailer available with yet more of the bright colors and those super catchy ABBA songs. Really, it looks like one long dance party with an adorable Amanda Seyfried and a lovely, girlish Meryl Streep at the center of it all.