Prince was seated in the audience before taking to the stage Enlarge Image

The crowd at Matthew Williamson's show were astonished when the first two models on the catwalk started to dance.

Prince then began singing into a microphone from his seat before jumping up and performing on the runway.

The audience, including Sting's wife Trudie Styler, took to their feet and snapped photos on mobile phones.

"He really wanted to do this, and you don't say no to Prince," Williamson told Reuters after the show, which included identical twin dancers and a full band .

Tour finale

Prince, wearing sunglasses, a black suit and top hat, performed his 1987 hit single U Got the Look, originally a duet which Scottish singer Sheena Easton.

The show closed with one of his signature songs, Kiss, after which Williamson sent his models down the catwalk.

The star, whose career has spanned four decades, is reaching the end of his 21-night residency at London's 02 arena.

Tickets for the finale, on Friday night, are exchanging for hundreds of pounds on internet auction sites like eBay, with some aftershow tickets fetching more than �500.