Fighting between Reese Witherspoon and Vince Vaughn is reportedly threatening to disrupt filming on their new movie FOUR CHRISTMASES. The actors co-star in the romantic comedy, but according to reports the shoot is being hampered by the pair's arguments over Vaughn's laid back attitude to work. Witherspoon is allegedly furious the Wedding Crashers star refuses to adhere to her super-efficient acting methods. A source tells the New York Daily News, "Vince rolls onto set in the morning looking like he just came in from a night out, while Reese will arrive early looking camera-ready. "Then Reese tries to force Vince into blocking out each scene and running through their lines as Vince tries to convince her that he's an ad-libber and wants to play around and see where the scene goes. "She's a one-take perfectionist and Vince likes to try it a few different ways. Sometimes Vince will be standing behind her and he has this look on his face that he just wants to kill her!"