Hathaway has a nice voice based on her impressive live singing at the Oscar with Jackman. Don't forget also that these stars will not be singing live; They will have the benefits of having professional sound mixers, editors, producters, etc., making their voices sound 10 times better for the film. Crowe is the wildcard. Maybe he'll talk his way through the song. He can't be any worse than Pierce Brosnan in Mama Mia .