Katy Perry wants to have sex with Rihanna.

The "Firework" singer was asked if she would ever collaborate with her close friend and though she ruled out working on a record with the star, she joked that they would do something more intimate instead.

"No, but we're going to have sex," she joked. Katy was also asked if she listens to her own music when she is having sex and said it would be "over the line."

"I'm not a narcissist! OK, I'm a narcissist, but that would be over the line. Having sex to your own song, that's horrible. I'm a good Christian girl," she said. The raunchy conversation continued with Katy questioned on whether she has ever had a threesome, but the star would only say "no comment."

Despite her jokes, Katy has previously confirmed she will collaborate on a song with Rihanna, but wants to make sure it is "iconic."

"It's one of those things that's got so much build up that we have to deliver...I definitely want to do something that is so iconic. We're both busy but we planted the seed two years ago. How disappointed would you be if that song came out and it's no good?"