THE OC star Mischa Barton is set to shock fans by playing a sullen dominatrix in a new ad campaign for fashion house Bebe. The pretty actress will be seen on billboards across America wearing Bebe outfits, posing alongside scantily-clad manservants. In one quirky photo, taken by top snapper STEVEN KLEIN, Barton digs her high heel stilettos into a male model's bare back, while, in another, a hunk wearing nothing but a pair of bikini briefs kneels obediently beside her as she strikes a fierce pose behind a veil.