Amanda Holden has joked that Simon Cowell could be a co-father of David Walliams' new baby.

The Little Britain comedian recently became a father with wife Lara Stone but Holden said on Alan Carr's Chatty Man that there might be a third party involved.

The Britain's Got Talent judge suggested that Cowell and Walliams may have mixed up their sperm together before the conception took place. She said:

"I said he looks more like Simon. They're going to make brilliant dads. I think they put it all in a test tube, gave it a little shake and Lara took it."

Holden also commented on recent reports that her colleague Cowell doesn't wear any underwear, revealing:

"He stood up, sorted himself out and I saw it dangling. I could almost tell what religion he was. I said, 'Darling, have you got knickers on?' He went, 'No, darling - I love to go commando. I like to be free'."