Danny Devito (WENN.com)

Movie star Danny DeVito is set to stun fans in his hit TV show's Christmas special - by appearing completely nude.

The pint-sized star is seen bursting out of the fabric of a sofa at a party in the It's Always Sunny in Philadelphia DVD special, A Very Sunny Christmas.

His sweaty character appalls party guests, who shriek and run from him as he stumbles past them, and DeVito admits it's a scene he always wanted to shoot.

He says, "I've been doing It's Always Sunny in Philadelphia for, like, four years now... and I'm so excited about it... In the beginning... I said to them (co-writers and cast), 'There's no holds barred; I want to do it. If we're going to do a show that's got that kind of edginess and craziness... I want to pull out all the stops.'"

But he admits when it came to baring all onset, it was a little strange: "I got there and there's, like, 100 background extras; they're all standing there, I've never seen them before (and) I walk in (looking) like a greased pig.

"The first take was a little disconcerting." (KL/WNVKIM/MT)