That's because she feels like a cartoon character in real life. "The Smurfs movie was really fun for me cause a lot of times, you know, 360 days out of the year I feel like a cartoon. So I thought playing a cartoon was a natural thing to do," the singer said Saturday at the launch of her new perfume, "Purr," in Mexico City.

"With 'The Smurfs' I get to walk into the studio and I can be in my pajamas and I make a really cute little voice, which is kind of a mixture of my voice and a little voice," she said. The Grammy-nominated pop star will also take on a more grown-up acting role as a guest star on an episode of the CBS comedy hit "How I Met Your Mother."

Perry said she was excited about performing at the Feb. 13 Grammy Awards, where she has been nominated for four awards, including album of the year for "Teenage Dream." "It's going to be an amazing performance. I don't want to get too much into it but it's going to be a medley of 'Teenage Dream,'" she said.