Mischa Barton @ Sundance Film Festival 2008

Mischa Barton arrives at Salt Lake City airport on Sunday to attend the 2008 Sundance Film Festival in Park City, Utah. She will be promoting Assassination of a High School President, her new teen comedy about stolen SAT exams.

Earlier this month, the 21-year-old former O.C. actress was spotted leaving “The Good Shepherd Catholic Church” in Beverly Hills to attend confessional. She was recently arrested for DUI, possession of illegal narcotics and driving without a valid license.

According to E!, Mischa has hired publicists Howard Bragman and Lisa Perkins of L.A.-based Fifteen Minutes, and attorney Anthony V. Salerno to be her legal counsel. (Bragman, an openly gay publicist, was hired by Isaiah Washington to handle damage control for using the F-word.)

Mischa was also recently photographed walking her two dogs, Ziggy and Charlie, in a Beverly Hills park.

15+ pictures inside of Mischa Barton @ 2008′s Sundance Film Festival…