God bless him, I mean a lot of times you get non-actors on a set and they get really self-conscious, especially when doing something crazy like singing along with Phil Collins. They get sort of reserved and self-conscious. Mike [Tyson] completely trusted Todd [Phillips] and totally put everything into it.

The scene [in The Hangover] where the tiger actually pops up behind us, that's actually a Jim Henson tiger puppet. The Jim Henson Company actually supplied that tiger. And it's really cool. Its entire face moves. It has like all these little motors in its eyebrows and cheeks and mouth. It was amazing.

When we were not shooting [The Hangover] we were sleeping, so pretty much every waking moment we spent together. And, you know, Bradley [Cooper], Zach [Galifianakis] and I were acquaintances before the movie started but we became good friends very quickly and spent so much time together that it was just inevitable we were either going to really hate each other or really like each other. Thank god it turned out to be the latter.

Improvisation is about finding the best joke or the silliest way to get something across. Improvising conflict is always fun because you can just go for it.

I didn't mention the tooth thing to anyone until it became clear that...we started to discuss just taking it out of the movie [The Hangover] because we couldn't find anything that worked and they couldn't afford to do a full like digital effect. So that's when I called my dentist and it worked out.

I was just fooling around with the piano and Todd [Phillips] was like, 'Hey there's a great spot in the movie [The Hangover] where we need a little bit of a breath in the narrative. You should write a song and stick it in there.' And I was like, 'Well, what should the song be about?' And he said, 'The tiger.' 'Oh, okay.' So I went off and I wrote this song. I came back and Todd and I tinkered with it a little more and then we shot it right then. It all happened in a day.

[Mike Tyson] was fantastic. Well, here's the cool thing about Tyson. It turns out he's a huge fan of Old School, which was one of Todd Phillips' earlier movies. So he got to the set and he already liked Todd and he trusted Todd.