Maybe you heard the rumours that tempers are flaring on the set of the new comedy FOUR CHRISTMASES. There's nothing funny about reports that stars Reese Witherspoon and Vince Vaughn are clashing at every turn. Seasoned pro Robert Duvall may be sorry he ever signed up to costar in this holiday flick about a couple trying to juggle Christmas visits with all four of their divorced parents. Oscar winners Kathy Bates and Glenn Close are still in talks to play the moms in this one, so if things don't smooth over soon, they might prefer to opt out altogether.

Any kind of collaboration can be tough when the stars have entirely different work ethics and, by all accounts, that's the case here. Vince has a casual, laid back approach and likes to improv, have some fun and, according to a source from the New York Daily News: "rolls onto set in the morning looking like he just came in from a night out, while Reese will arrive early looking camera-ready." You cannot create chemistry...it's either there or it isn't.

For all the hoopla about the alleged romance between Reese and her RENDITION co-star Jake Gyllenhall, they never shared screen time in the flick so it's impossible to judge what kind of on-screen sparks they might ignite. Who could forget the passionless match-up of then-spouses Tom Cruise and Nicole Kidman in EYES WIDE SHUT!?

I can only tell you from interviewing Vince and Reese (separately) that this clash of Tinseltown titans seems likely to be accurate. VV was as jolly, laid back and easy-going a star as I have ever met, while RW struck me as a very self-conscious and controlled individual. Add the fact that she is also a Producer on this film and I'm sure there is an added pressure on her to make everything "just right." Maybe some of his comfortable confidence will rub off on her and they can get back to business.

If not, any tips for them on how to work it out? Any experience of having to deal with a co-worker you just didn't "click" with??