Matt Damon and Heath Ledger are obviously the heart of the movie. But at first I thought Matt would play Jake, because he's usually more of an introspective and sensitive character, and Heath would play Will, because he's usually cast as the straight-ahead hero. But then Matt came into our first meeting and said he wanted to play Will. I wasn’t sure about it at first, but then Heath came to me and said 'Well, I'd like to play Jake.' And then I realized that this was absolutely the right thing, because I love to cast against type and turn things completely around. And it worked, because they are both very surprising in these roles. It's not what you've seen before from either one.
I've never seen anyone work as hard as Matt did to become a character so unlike who he really is, and also so unlike any character he's played before. His entire bearing is completely different and I hope the audience will respond with the same excitement that I did to it. Heath is someone who the world is used to seeing as a more conventional hero, but here you see that he also has another kind of nervous, quiet side to him that's very intriguing. Like Matt, he simply wouldn’t give up until he got the role right. They are both very impressive.