Give Your Cocktail Dress the Night Off

For a stop at The Late Show with David Letterman, Emma Watson picked a Saint Laurent by Hedi Slimane suit, worn over a white button-up done all the way up to the throat and Christian Louboutin Apostrophy slingbacks. The look is menswear for her at its best: there's nothing obviously sexy about the fit, but it still has a sizzle you can't deny.