Katy Perry reportedly fled from a London nightclub to avoid a run-in with Russell Brand.

The 27-year-old 'Part Of Me' hitmaker was apparently singing karaoke with friends in a Las Vegas-themed private room at Mahiki in Mayfair, when she heard her soon-to-be ex-husband was on his way.

A source told Metro newspaper: ''She wanted to spend the night singing in the room as it's where her best mate Rihanna normally comes to play when she is in town.

''Katy was having a great night but bolted out the door when one of her sidekicks stunned her by telling her Russ was about to turn up.

''Rather than risk an awkward run-in, Katy didn't take any chances and ordered everyone to move on to a club in Chelsea instead.''

The former couple split when 36-year-old Russell filed for divorce in December citing ''irreconcilable differences''. Katy has since hinted she is planning to tell all about her failed marriage in her forthcoming biopic.

She told BBC Radio 1: ''I'm having a film of my own come out. It's called Katy Perry: Part Of Me and it's in 3D so you don't need any hallucinogenic to go, just glasses.

''[It will cover] all of last year, which was the most intense year I think of my life. You'll appreciate this film because I feel like if you know everything about me, which you do - kind of - you'll know even more. It's basically like being in bed with me.''