Last Night's Look: Hit or Miss?

Vote on this week's styles including January Jones, Reese Witherspoon and more stars! You decide – are they fashionistas or flops?

RIHANNA

The singer takes a break from Katy Perry's bachelorette weekend in Las Vegas, looking white-hot in a fitted Hervé Léger mini dress and nude pumps as she heads backstage to meet the cast of Cirque du Soleil's KA at the MGM Grand.