Reese Witherspoon and Vince Vaughn are clashing on the set of their new film, "Four Christmases," spies told the New York Daily News.

Famously alpha personality Reese — who named her production company Type A Films — is clashing with Vaughn's laid-back approach to work, the News reported.

"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," said the San Francisco source. "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."

Click here for the Daily News report

However, the romantic comedy about a married couple who spend a Christmas with each of their four divorced parents remains on schedule and on budget.

"She's a one-take perfectionist and Vince likes to try it a few different ways," said the News snitch. "Sometimes Vince will be standing behind her and he has this look on his face that he just wants to kill her!"