Britney Spears proved that she'll do just about anything in the name of good - but not necessarily clean - fun on Jimmy Kimmel Live last night. The pop star stopped by for a hilarious clip with the Jackass crew in which she recreated their 'Poo Cocktail Supreme' in a Porta-Potty slingshot. It's all part of her promotional tour in support of her album, Femme Fatale, which dropped yesterday, and Brit took the stage on the late-night show to show off some sexy new costumes and sing for the crowd.