Jim Carrey has reportedly given girlfriend Jenny McCarthy his permission to sleep with Justin Timberlake - if Justin is willing.

Jim and Jenny have been dating since December 2005 but Jenny told Jim she had a long standing crush on the former NSync star.

A source told the National Enquirer that they overheard Jenny explaining the deal to a friend: “Jenny was at Los Angeles’ W hotel with a friend and she was saying Jim has given her the go-ahead to fool around with Justin should the opportunity ever arise!”

“Either he’s joking or he’s very understanding.”