The Office star John Krasinski is enjoying the success of his hit NBC sitcom, but his most recent film with George Clooney has definitely kept his ego in check. "I think a lot of people when we were down shooting thought that I was his personal assistant," says John, laughing about how he was hardly recognized as fans ogled Clooney.

Still, John sees his role in Leatherheads as an invaluable opportunity because of his "strategic" contract negotiations with Clooney, who also produced and directed the film. "I said, 'I will do this movie if you make me People's sexiest man,'" John jokes. "It worked for Matt Damon!"

Once they ironed out the details, the real jitters settled in for John. He was petrified that Clooney, a notorious prankster, would hit him with a big zinger during the shoot so he remained on high alert. "Every night -- I swear to God -- I looked under my bed and looked in my closet," John says. He made it through the shoot safely, but apparently he needs to be careful in Rachael's studio. (Click here for exclusive backstage footage of the prank!)