The bad boy is behind bars. Jason Wahler has voluntarily turned himself in and surrendered to jail officials in Issaquah, Washington, October 25, to do time for assault, criminal trespassing and underage drinking. He was arrested in April.

"[Jason Wahler] is making amends for his past arrest," his rep tells Us Weekly exclusively. "This is not a new arrest." A bit surprising, but that's good news.

The star of Laguna Beach and The Hills is set for a sentence of 30 days in the slammer, but his rep said, "we hope it's cut short." So do we. So do we.

At least Jason Wahler, 20, is keeping busy behind bars. And we're not talking about conjugal visits from his sexy fiancee Katja Decker-Sadowski.

Wahler, the ex-boyfriend of Lauren Conrad, recently signed on to play a jock in the horror flick, 10,000 Doors. Shooting begins later this month.

"He is currently spending his time behind bars reading the script and getting ready for the role so he has a lot to do," says Jason Wahler's rep.