Mischa Barton Gets a BBQ Boost

Mischa Barton walks around in Marc by Marc Jacobs flats while helping mobile phone service Boost Mobile host a BBQ on Saturday at Project Beach House in Malibu, Calif.

The 22-year-old former O.C. star was seen grabbing a Hilton Pet Friendly dog bed for her little puppy.

Pete Wentz‘s baby’s mama Ashlee was also spotted hanging out in a Boost Mobile Cabana while he deejayed the BBQ.

15+ pictures inside of Mischa Barton getting a BBQ boost…