The 23-year-old, who starred in "Harry Potter and the Philosopher's Stone", said that after "Burlesque" and "Footloose", she did not want to be part of another musical.
"At first I was like, 'Yeah, I don't think I want to do another musical... Of course, you have to get your foot in the door somehow, so 'Burlesque' and 'Footloose' made sense. But I wanted to expand and grow as an actress," she said.
But she changed her mind and carried forward with this role when director Adam Shankman told her that the "Mission Impossible" star had been signed up as the lead against her. "He said, 'You know, Tom Cruise is in it.' And I was like, 'Right - I'll do one more musical'," she said.