Reese Witherspoon has reportedly refused to shoot a sex scene with Vince Vaughn after the pair clashed on the set of their new romantic comedy "Four Christmases" says The Digital Spy.

Last month reports came out that the actress was irritated by Vaughn's 'relaxed' attitude during filming, regularly turning up on set looking like he had been out all night and that he preferred ad-libbing to rehearsing with his co-star.

An insider told the New York Post: "Reese has an issue with the scripted love scene. It is meant to be a funny, American Pie-style romp, full of bumps and laughs, but Reese is of such a prude, she thinks it's just too much."

Vaughn is one of the producers of the movie, which is scheduled for release next Christmas.