The polka-dot-wearing actress makes a cheerful arrival to the Late Show with David Letterman. Plus: Blake Lively, Gavin & Gwen, Nick Jonas and more


After dishing to New York radio station Z100 about her new "girl anthem" "Womanizer," Britney Spears keeps things fluid while shopping at Barneys New York in Manhattan on Monday. The video for the single debuted during Monday's episode of The Hills.