Former star of The OC Mischa Barton was arrested for DUI, possession of illegal narcotics and driving without a valid license early this morning.

The frail, 21-year-old actress was pulled over early this morning around 3:00 a.m. as she was driving in West Hollywood, Calif., and is still in custody.

Mischa Barton is being held on $10,000 bail. No word on what her BAC was, but seeing as she weighs about 75 pounds, one drink would probably get her smashed.

Mischa Barton is the latest celebrity DUI arrest.

The arrest of the actress was first reported by Hollyscoop.com. Mischa Barton was under the influence and driving a white Range Rover without a license.

Soon enough, we'll have the newest, drunkest addition to our gallery of celebrity mug shots, which already includes Mischa's skinny BFF, Nicole Richie.

More details on this story as it develops ...