It would appear that tensions on the set of Four Christmases are at an all time high, as the off-screen feud between stars Vince Vaughn and Reese Witherspoon continues to heat up. Last month we told you how both actors were a bit peeved over the other's work ethic. Witherspoon didn't like the fact that Vaughn would show up to the set unprepared, laid-back and ready to improv (after a long night at the bar), while Vaughn seemed pissed that Witherspoon refuses to lighten up and go with the flow. Perhaps that's why pal Jon Favreau was brought in for a late inning role, so that he could keep Vaughn in check and not let the guy ruin the entire flick?

Now, Digital Spy tells us that things on set aren't getting any better. Witherspoon apparently has a problem with one of the scripted love scenes between her and Vaughn, and doesn't want to go through with it. Says a spy: "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." And this is the girl who was just named the most-liked celeb in 2007? Granted, I wouldn't blame Witherspoon for not wanting to get dirty between the sheets if her partner reeks of alcohol and refuses to go strictly by the script. Who knows what he would do once they were in bed together; for all we know, he could go crazy with the improv, whip out his Johnson and start wagging it around. Sheesh, no Oscar winner deserves that sort of disrespect.

Then again, a scene like that would probably go down as one of the funniest of the year. Poor Reese. If you slack off on set, you get reamed, and if you show up every day on time, with your ultra-professional cap on, you still get reamed. I guess you're damned if you do, and you're damned if you don't. Hopefully the film won't suffer because of this feud (though the press junkets should be very interesting).

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