Dax Shepard Still Punking Kristen Bell

12/22/2007 11:55 PM PST
Ashton Kutcher's original trickster on "Punk'd," Dax Shepard, parlayed his ability to screw with celebs into a successful career of screwing with the general public -- by wrapping himself around one hot Hollywood blonde after the other. Where are the hidden cameras now?

Kristen Bell left her car at a shop to be serviced Friday, and piled into Dax's truck to go grab a bite to eat -- where Dax held back the urge to make Kristen think her car exploded during the tune-up. He's so unpredictable!

Except when it comes to women ...