ATHENS, GREECE - JUNE 28: (L-R) Dominic Cooper, Colin Firth, Amanda Seyfried, Stellan Skarsgard, Meryl Streep and Pierce Brosnan attend a photocall for the movie 'Mamma Mia!' at the Lagonissi Grand Resort on June 28, 2008 in Athens, Greece. (Photo by Milos Bicanski/Getty Images)

The whole cast is back plus CHER is the Grandmother who is not invited to the party, but shows up anyway.