My process is to be by myself when I record. It's quite an emotional performance to pull off when someone else is in the room. I prefer to go away and have my own time with it, bring it in later.
You can relax more when you're playing a silly character than when you're playing a really rigid character. But to be fair, I think George Clooney is a bigger teenager than any of the 'Twilight' cast. He's the guy throwing a football at your head and then hiding around the corner, pretending it wasn

