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ET confirms former "The O.C." star MISCHA BARTON was arrested early Thursday morning in West Hollywood. At 2:46 a.m. sheriff deputies stopped her vehicle when they spotted it allegedly straddling two lanes of traffic and failing to signal when making a turn. It was determined she was an unlicensed driver and was allegedly driving under the influence of an alcoholic beverage. The 21-year-old actress is still in custody with her bail set at $10,000. The investigation is ongoing at this time.