Tongue spat: Katy kissed a girl and didn't like it

Miley Cyrus has slammed Katy Perry's reaction to their public kiss. Photo/AP.

Katy Perry refused to kiss Miley Cyrus because she doesn't know where her "infamous" tongue "has been", and now Cyrus has hit back at the Dark Horse singer.

The pair locked lips last month during Cyrus' Bangerz world tour, but Perry pulled away after the Adore singer attempted to slip her tongue inside her mouth.

Perry told Australia's Sunrise: "I just walked up to her to give her like a friendly girly kiss, you know, as girls do, and then she like tried to move her head and go deeper and I pulled away. God knows where that tongue has been. We don't know! That tongue is so infamous!"

However Cyrus hit back at the comments on Twitter, referring to Perry's ex-boyfriend John Mayer, who has previously dated Jessica Simpson and Jennifer Aniston.

Girl if ur worried abt where tongues have been good thing ur ex boo is ur EX BOO cause we ALL know where THAT ?? been pic.twitter.com/IO6KwRzw2y

Meanwhile, Perry kicks off her own Prismatic world tour on May 7, so she has put herself on a strict diet in a bid to be in the best shape she possibly can for the shows.

She said: "It's a lot of work, I have to be very focused. Right now I've cut out all alcohol, all fatty foods, a lot of dairy. I go home and I'm going to have like mostly vegetarian, with some protein on the side like chicken.

"I'm almost 30 guys, my body does not snap back any more!"

- Bang Showbiz