Ke$ha has admitted that she has seen Katy Perry in the buff.

The singer told Capital FM that the pair have been good friends for a number of years - and it seems their friendship stretches far enough to see each other naked.

The 'Tik Tok' star was asked which person tickles her fancy the most - Perry or her former husband Russell Brand - with Ke$ha replying:

"They're both hot but I wouldn't get them at the same time and probably not in the same room. This is too hard, I don't know."

She continued: "I'd probably [pick Katy Perry] – I'm friends with her. We've seen each other naked it's fine. It was cool. We've been friends for like years."

The general public meanwhile got a good glimpse of Katy Perry in the nude at the Grammys on Sunday (February 10), with the 'Wide Awake' star showcasing her ample bosom in a revealing dress - much to the surprise of TV's Ellen DeGeneres, who can be seen admiring Perry below.