Supermodel Kate Moss is swapping Burberry and Chanel for a lumpy tracksuit and hoodie for her theatre debut as the best friend of queen of the Chavs, Vicky Pollard.

Moss, 32, has been asked to take part in a charity performance of Little Britain - and she jumped at the chance.

The news of her part in the Comic Relief performance this month came as Moss made a brief appearance at a party to mark 90 years of Vogue magazine last night.

As she has graced more Vogue covers than anyone, it was only fitting that she should make a star appearance. But Moss, who arrived with Pete Doherty, left the Serpentine Gallery after 15 minutes for a night out in the East End. She and Doherty had a few drinks at the Golden Heart in Shoreditch, described by regulars as an old-fashioned London pub.

They went on to the 93 Feet East music venue to catch a live set by Manchester three-piece I Am Kloot.

A guest at the party said: "Kate only stayed long enough to have one drink and ran off after she'd had her picture taken. She had to drag Pete away because he was deep in conversation with Bryan Ferry's exwife Lucy."

Moss recently snubbed the British Fashion Awards, where she was named model of the year, preferring to go for dinner with Doherty in Clerkenwell.

Moss is keen on making her career more diverse and has struck a £3 million deal to design a range for Topshop. Now she will make her London theatre debut with Little Britain stars David Walliams and Matt Lucas.

Insiders say she is likely to appear as a shellsuit-wearing chum of mouthy teenager Vicky Pollard.

Walliams told the Standard: "I've known Kate socially for a little while and she and Pete came to our show one night and liked it.

"So we thought, let's be cheeky and see if we can convince her and she was up for it. Kate's funny in her own right so we think it'll be brilliant." He confirmed: "It'll be a speaking role but I don't want to give too much away. When you see her and what she'll be wearing and doing it'll be a big surprise."

Walliams added: "Kate has natural comic talent. It's just that most people don't know it because beautiful people aren't allowed to be funny. But I know she's going to be great. It's a real coup and we're absolutely chuffed."

Jonathan Ross and Russell Brand - who had a brief fling with Moss - are also in the show at the Hammersmith Apollo on 22 November.

Tickets for the charity show go on sale tomorrow through www. ticketmaster.co.uk