Fresh from treating Garden State to her affected bohemianism, Natalie Portman puts her sorority-smooth bum forward as the world's most unlikely stripper … and somehow emerges even less scathed from her latest brush with potentially fatal miscasting. There's something accessible about the woman, and it extends to co-stars Julia Roberts, Jude Law and Clive Owen, who gamely reinterpret playwright Patrick Marber's cruelty-soaked drama about partner swapping in modern-day London. Beyond the charisma of its cast, however, the movie is unfortunate proof that a moderately successful play does not a worthwhile film make, even when its author himself is doing the adapting (and the esteemed Mike Nichols is directing). The forward-leaping narrative that seemed so daring on the stage merely comes off as jarring, the copious chance meetings are particularly improbable outside the pressurized environment of a theater, and the bitter soliloquies ring stilted in ways even the capable actors can't overcome. A formerly startling string of episodes has become a prurient, static exercise in monochromatic tongue-lashing.