Sir Paul McCartney stunned the crowd at the Coachella music festival by joining Afrojack on stage.

The Beatles legend amazed revellers at the Californian festival over the weekend when he popped up at the Dutch house DJ's set in the dance tent and started spinning some tunes in the booth as girlfriend NANCY SHEVELL looked on.

A source told The Sun newspaper: "It was a weird and once-in-a-lifetime experience. Macca popped up in Afrojack's set and was having it on stage behind the DJ booth. Nancy was standing behind him like a typical house DJ's girl.

"I think a lot of the ravers thought they were seeing things - when word spread around the site, everyone thought it was a wind-up."

Usher later joined Paul on stage and the two had a dance-off in front of thousands of clubbers.

The three day event saw headline sets from Kings Of Leon, Arcade Fire, Kanye West, who closed the festival last night (17.04.11) saying it was the "most important show" he had performed since his mother died suddenly in 2007.

Arcade Fire performed another of the most sought after set sets of the weekend, which culminated with the band releasing hundreds of huge colour changing balls into the audience.

The spectacle was a collaboration with artist Chris Milk called 'Summer Into Dust', part of The Creator's Project, an initiative by Intel and Vice magazine, which paired a number of artists with bands for audio visual presentations over the weekend, including Spiritualized and Jonathan Glazer, Interpol and Animal Collective.