How do we know this? Well because she tweeted about it of course.
"Remember that surprise song I recorded for my boys?" she began. "It's coming soon!"
To be honest, we don't remember said song, but still.
She then went on: "#OohLaLa for #TheSmurfs2 :) Stay tuned for more…"
She then said this to a press statement:
"I have always loved the Smurfs as a kid and now my boys are the biggest Smurfs fans ever. I wanted to surprise them with a song in the movie. I know they'll think it's Smurftastic!"