Music mogul Simon Cowell was left red-faced during a UK TV interview after fellow guest David Walliams aimed a string of gay jibes at the music mogul.

The pair filmed The Jonathan Ross Show to promote the latest series of Britain's Got Talent, which they both appear on as judges.

However, Cowell - who recently called off his engagement to Mezhgan Hussainy - was left squirming in his chair as the cheeky Little Britain comic poked fun at him during the chat.

"The main question I get is, 'Is Simon gay?' Even my mum asks," Walliams told Ross.

"She says, 'He's nice. Is he gay?' Even my mum was going, 'Yeah he is really nice - is he gay?'... Well we know the answer to that. With the gay thing, the jury is still out."

Cowell was left cringing at the remarks, telling his TV co-star: "Most of this will be edited out."

But Walliams refused to give up, and quipped: "At 12 o'clock at night you're working quite hard - because that's when the ladyboys come round."