Chris Martin serenades Cheryl Cole

Chris Martin and Gwyneth Paltrow serenaded Cheryl Cole over the phone.

The couple had called each member of Girls Aloud - Cheryl, Nadine Coyle, Kimberley Walsh, Nicola Roberts and Sarah Harding - individually to convince them to support Chris' band Coldplay.

But when it came to persuading 'The X Factor' judge Cheryl, the pair decided they needed to make an extra-special effort and sang a rendition of the girl group's hit 'Sound Of The Underground'.

A source told Britain's The Sun newspaper: "The girls were buzzing to get a personal call from Chris. They never thought he would be such a big fan.

"After hanging up from Chris, Nicola called Cheryl to tell her the good news, but Cheryl had come off the phone from him minutes before and was still in shock.

"Chris roped in Gwyneth to give Cheryl an 'X-Factor'-style performance.

Gwyneth belted out the girls' hit single down the phone with Chris joining in."

'Iron Man' star Gwyneth - who is reportedly planning to open a worldwide chain of gyms - also asked Cheryl to invite 'The X Factor' winner Alexandra Burke to sit next to her in the audience at the concert.

Chris has made no secret of his love for Girls Aloud.

He recently said: "Girls Aloud are my favourite girls in the world, aside from my wife and daughter, of course! But they definitely come third to eighth."

Girls Aloud will support Coldplay at London's Wembley Stadium on the September 19 date of their UK tour.