Jessie J wants Katy's boobs

Jessie J's tweeting Katy Perry after meeting her Down Under and they're already discussing swapping body parts!

The Price Tag star, who will be at the Summertime Ball in June, is clearly a big fan of Katy's cleavage after seeing her on stage in Sydney.

In a message on Twitter, Jessie J said: "Just met @katyperry. The show was incredible, she is beautiful and so sweet. I wish I had her boobs lol #greatnight."

Perry replied, "Nice to meet you too, you're a DOLL," she wrote on Twitter. "And p.s. the offer still stands... I'll trade my tits for your gams!"

Both stars are currently on separate tours of Australia.