The last time Keira Knightley got an Oscar nomination, she was flouncing around ye olde British manor houses in hooped skirts ("Pride and Prejudice, " 2005), so we must wonder if she can do so with her next release too. In "The Duchess," we not only see her flouncing in frilly dresses again, but out of them too, flashing naked derriere as she bed-hops. With a limited release in mid-September by Paramount Vantage, this might be well-timed for Oscar attention. It's based upon a real-life person and one whose life story mirrors Princess Diana (focus of Helen Mirren's best actress victory for "The Queen"), so Knightley may seduce Oscar voters this time, if, as rumored, some of them really do have a heart, and if they wish to make up after cruelly spurning her turn in "Atonement."