LAS VEGAS, NV – DECEMBER 17: Britney Spears ends a night of celebration with fiance Jason Trawick at the Chateau Nightclub on December 17, 2011 in Las Vegas, Nevada. PHOTOGRAPH BY GSI / Barcroft Media UK Office, London. T +44 845 370 2233 W www.barcroftmedia.com USA Office, New York City. T +1 212 796 2458 W www.barcroftusa.com Indian Office, Delhi. T +91 11 4101 1726 W www.barcroftindia.com