PARIS HILTON's mum is to play TOM CRUISE's wife in a hilarious scene in BEN STILLER's new movie TROPIC THUNDER.

Kathy Hilton has told friends she has a cameo in the upcoming summer comedy.

A source tells In Touch magazine, "She filmed the scene last winter and didn't even tell her kids because she wanted to surprise them.

"She raved about Tom. She said he was so warm and friendly and made her very comfortable."

News of Cruise's surprise cameo in the film hit the headlines late last year (07) when the movie superstar was spotted sporting a bald hairpiece and prosthetic belly on the set of the film, which stars Stiller, Jack Black and Robert Downey Jr.