New Dad Matt Damon Piles on Weight in Bourne Ultimatum  8/6/07

Matt Damon hopes movie fans aren't too eagle eyed when they watch him in sequel The Bourne Ultimatum - because he ended the film 20 pounds heavier than he was at the start.

The actor blames his heft on fatherhood and the fact he couldn't tear himself away from his new family to spend hours at the gym in between shoots.

Damon admits he was much more disciplined while making the first two Bourne movies.

He explains, "I started the movie in really good shape and one thing about having kids has made me realize that I used to not have any life.

"In the old Bourne movies we'd work six to eight weeks, work for 15 hours, go to the gym for two hours, then I'd eat a little something, and go to sleep every day. That's all I did. And on Sundays I slept all day.

"On this one I showed up in my Bourne shape and, after 16 hours, I wasn't going to the gym; I wanted to see my kid, so, by the end of the movie, I'm 20 pounds heavier than I was in the beginning."