The improv stuff, that's always surprising so a lot of times that's really funny.

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.

The biggest thing that comes out of improv that gets built on is just character traits. You know, for me the singing was born out of improv.

Alcohol causes conflicts, firearms resolve conflicts.

This word gets overused in describing actors but I think it applies to Mike [Tyson] in this case - he was totally fearless. He jumped in and played with us comedically and improvised a lot. A lot of jokes in those scenes with him are from him improvising.

I feel like I'm worried about my later years in life because I feel like I'm using up so much good karma right now. There's going to be some sort of karmic backlash somewhere down the road.

As much as you do get beat-up doing even small action sequences, it's incredibly fun.