<Li> Colin Firth as Harry Bright, Sophie's possible father and a British banker; based on "Our Last Summer", which he sings at one point . </Li> <Li> Stellan Skarsgård as Bill Anderson, Sophie's possible father, a Swedish sailor and travel writer . </Li> <Li> Dominic Cooper as Sky, Sophie's fiancé, designing a website for the hotel . </Li> <Li> Julie Walters as Rosie Mulligan, one of Donna's former bandmates in Donna and the Dynamos; an unmarried fun - loving author . </Li>

Who plays sophie's boyfriend in mamma mia