Round one
The first punch
KATY PERRY threw the first punch, when she was asked to describe herself in an interview and replied, "Aha" I'm like a fatter version of AMY WINEHOUSE ans a skinner version of LILY ALLEN! "Uh-oh, gilfriend's not going to be happy.

Round two
The angry comeback
"You're not English and you don't write your own songs, shut up!" came Lily's angry reply, before blasting her american rival as a cheap imitation. "I happen to know for a fact that she was an American version of me, "ranted Lils. " She was signed by my label in America as, 'We need to find something controversial and kooky, like Lily Allen.' And then they found her. I think the lyrics and stuff are bit crass."

Round three
The barbed apology
Realising she'd clearly unleashed the beast in Lily. Katy decided a bit of backtracking was in order. But true to form, she couldn't resist one final dig. " I was just kind of joking and trying to be funny. I didn't mean anything by it. Comedians are not necessarily to be taken super seriously." Translation: " You have no sense of humour. And by 'kind of joking', I mean not at all."

Round four
The facebook sabotage
Take cover Katy, because now you've really rattled Lil's cage. The serial blogger has decided it's time to bring out the big guns, and mount an online attack. " I have Katy Perry's number, someone did me a favour. I'm just waiting for her to open her mouth one more time then it hits facebook," spewed Lily on her Facebook page. She also signed up to two new Facebook groups: " I hate Katy Perry And Her Dumb-A**Song I Kissed A Girl" and Katy Perry? Who In The Hell Does She Think's She Is?' Ouch, that's below the belt. Your move, Perry.