'Twilight''s Anna Kendrick on 'Punk' Co-Star George Clooney

First impressions can definitely set the tone of a relationship, and 'The Twilight Saga: New Moon' star Anna Kendrick tells ET what it was like to work with George Clooney on the upcoming 'Up in the Air,' in theaters this December.

"My first impression of George was that he was a punk," Anna tells ET. "It was a very, like, brother-sister relationship; he kind of made fun of me and I made fun of him right back."

She adds of their on-set antics, "If he hadn't been an amazing guy I wouldn’t have been able to do that."