Katy Perry has revealed that she thinks having a career in acting is much harder than in music.

The 28-year-old singer, who voices Smurfette in The Smurfs, reckons acting is not something you can just "roll into".

Speaking to Radar, the Teenage Dream hitmaker said: "It's definitely a lot of effort to be an actor, and it's not something just anyone can roll into.

"I think you get a lot of people thinking, 'If I can act, I can sing; if I can sing, I can act', and it's just not true."

She added: "I think that it's actually harder and it takes more time than a music career. You wake up at four or five am. That's commitment.

"If the movie would start filming at 11am then I would do it."

Perry, who is currently working on her third studio album, also said that music will always be her main focus: "I have it inside me and I'll never lose it."