Movies News Katy Perry backgrounds on Britney Spears' 'Smurfs 2' song 07/29/2013 Katy Perry says she sang in the background of Britney Spears' "Smurfs 2" song "Ooh La La!" Read More RELATED NEWS Jimmy Fallon's 'The Tonight Show' dropping to only four nights a weekAshley Tisdale announces birth of her second childSelena Gomez is a billionaire TAGS: Britney Spears Katy Perry
