Singers Katy Perry and Britney Spears' voice will be heard in one song in the forthcoming movie "Smurfs 2".
The song "Ooh la la" is sung by Spears and written by Bonnie McKee. Perry's vocals are in the background, reports eonline.com.
"Me and Bonnie secretly did some background vocals on that song. So maybe listen for our voices," Perry said at the movie's premiere here.
However, Perry hasn't had a chance to meet Spears in person, and said: "I can't wait to meet her."