Cheryl Cole surprised fans by teaming up with will.i.am at one of his recent UK gigs.

The Newcastle singer joined the Black Eyed Peas man at London's O2 Arena on Thursday (December 5) for a duet.

They ran through their 2008 track 'Heartbreaker', which featured on solo albums released by both artists.

Tweeting before the show, will.i.am said: "Unbelievable...#soldoutO2 thank you UK...#willpowertour...I never thought this could happen...#dreamsDOcomeTRUE."

It has been a busy time for Cole meanwhile, who has kept up appearances with two charity projects.

She became a stockbroker for the day recently as she answered phones for ICAP's annual charity day.

The Girls Aloud star also filmed scenes for UK soap Coronation Street as part of ITV's Text Santa campaign.