Everyone knows that Katy Perry is one of the featured voices in Smurfs 2 and Britney Spears contributed a song to the soundtrack, but now the secret is out -- Katy is an uncredited guest on Britney's song.
Katy told E! News that she and singer-songwriter Bonnie McKee are on Britney's "Ooh La La!" She revealed, "Me and Bonnie secretly did some background vocals on that song. So maybe listen for our voices."
Despite the fact she's on her record, Katy had yet to meet Britney. "I can't wait to meet her," she said. Judging by photos that popped up after the premiere, it appears that Katy got her wish.
Source: E! News