The American singer appears in My Blueberry Nights with Jude Law, Natalie Portman, Rachel Weisz and David Strathairn, and the 27-year-old's nerves were obvious on the first day of filming.
"When I heard the list of actors I felt absolutely terrified," she revealed. "I thought to myself, 'What have you got yourself into?' When I listened to the playback after my first scene with Jude my voice sounded like I had been sucking a helium balloon. You could all but hear my knees knock."