Jason Segel admits his naked body is always met with ''hysterical laughter''.

The 32-year-old star - who gave a Full Frontal performance in 2008 movie 'Forgetting Sarah Marshall' - says that people can't help but laugh whenever he strips off.

Appearing on the 'Today' show, he said: ''Apparently me being naked is funny - onscreen.

''In my personal life ... If I take my clothes off it's met with hysterical laughter, for some reason.''

But having lost 35lbs for new film 'The Five-Year Engagement', new girlfriend and 'Dawson's Creek' alum Michelle Williams hopefully won't be laughing at him.

Explaining the weight loss, he said: ''I was forced to lose weight for this movie. It was by the studio president!

''I was told it had to be conceivable that [co-star] Emily Blunt would ever choose me to be her husband, which I think is fair enough! I had to lose a good 35lbs.

''I didn't enjoy it but they sent a trainer to set and I had to work out twice a day and he would also watch me eat all day.

''What they didn't anticipate is that I'm very clever and I play a chef in the movie, so there were a lot of scenes in which I had to eat. So I paid my co-stars phenomenal amounts of money to mess up their lines during the scenes and I'd get to keep eating!''