Oops! Did Katy Perry Jump On Britney Spears' 'Smurfs' Track?

Perry sings secret backing vocals on Britney's 'Smurfs 2' song 'Ooh La La!'

It's the kind of superstar hookup of pop fan fiction dreams: Katy Perry and Britney Spears sharing a microphone to record a song. All right, so, technically, the dynamic duo weren't in the studio at the same time, but Perry revealed this weekend that you can hear her singing some of the backing vocals on Britney Spears' "Smurfs 2" single "Ooh La La!"

"Me and Bonnie secretly did some background vocals on that song," Perry told E! News on Sunday at the film's premiere about the song written by Perry's frequent collaborator, Bonnie McKee. "So maybe listen for our voices."

Now that she mentions it, those vocals did sound a bit familiar. But the sessions for "La La" were just a tease for Perry, who did her bit without actually being in the same room with Brit. "I can't wait to meet her," Perry said of Spears, who attended the premiere in, yes, a blue dress, with her sons, and video co-stars
, in tow.

Perry is back in her role of Smurfette in "The Smurfs 2" movie, where she stars alongside Neil Patrick Harris, Christina Ricci and Fred Armisen.

Britney was clearly excited about the movie's debut and the possibility of more work together, tweeting, "So great to see you Smurfette @katyperry! Can't wait for our Vegas date ..." Can we expect Perry to drop in on Britney's Sin City residency?
 Who knows?

The mutual admiration society extended to Perry's Twitter account, with the breathless tweet, "OMG!!!!!! I CAN'T I'M CRYING" under a picture of her and Spears about to embrace.

The day before the premiere, Spears teased fans with a nugget of information about her upcoming album. "Can't wait to get back into the studio to write and record next week," she wrote. "I really believe this album is shaping up to be a real #PieceOfMe."

After watching "Smurfs 2" with the boys, Spears wrote that play time was over. "Back to dance rehearsals, writing and recording."