Britney Spears' 2011 Wango Tango Evening

Stepping out for her guest co-host duties, Britney Spears was busy entertaining the audience at Staples Center in Los Angeles, California on Saturday night (May 14). The "Hold It Against Me" singer teamed up with Ryan Seacrest to kick of KIIS FM's 2011 Wango Tango Concert - with the show's lineup including Selena Gomez, Ke$ha and Jennifer Lopez. Tweeting about the busy day's plans, Brit wrote to