Ananova reports that Charlotte Church turned the role of Christine in the Phantom of the Opera movie because she refused to lose weight for the role. (Producers had been considering waifish stars whose musical abilities are more questoinable, like Katie Holmes.) Church told The Face magazine, "Yeah, my arse is a bit big but I'm happy with myself. As long as I can sing it doesn't matter about the fame, it's disposable. I won't conform to the crap."
Ananova is a little off in the article: Antonio Banderas hasn't been associated with the project for a while; in fact, producers have offered the role of the Phantom to Gerard Butler.