Prince Philip once called David Walliams "a nut" for swimming the English Channel.

David Walliams

David Walliams

The 'Britain's Got Talent' judge swam the ice cold sea from Dover in Kent, South East England to France in 2006, and has revealed the 95-year-old royal - who is the Queen's husband - made the cheeky remark in front of his mother.

Speaking on a new ITV documentary to mark the Diamond Jubilee of the Duke of Edinburgh's Awards, Walliams, 45, recalled: "It was the year that I swam the Channel and he asked, 'Is this the nut who swam the channel?'

"And he went, to my mum, 'Any more nuts in your family?'

"To which my mum said, 'No, just the one Prince Philip', as he walked out the door."

And it's not the first time the 'Little Britain' star's mum has had a funny encounter with a member of the royal family.

In October, Walliams was at an event at the Royal Academy of Arts to celebrate Queen Elizabeth's contribution to British arts with his parent, and admitted she made the 90-year-old royal think when she informed her they had met 10 years ago.

He previously shared: "My mum said something really funny to her.

"She said, 'I met you 10 years ago actually.' And I thought, 'I'm not sure she'll remember because the queen has to meet about 500 people a day.'

"I could see the queen thinking, 'Who is this lady?'

"But then my mum explained that we met her after I swam the Channel and it did seem to ring a bell.

"My mum was particularly happy because we were standing next to Rod Stewart, and Rod was really nice to her and they had a good chat.

"So it was all happening at once. My mum meeting the queen and Rod Stewart at the same time. It doesn't get better than that."

The documentary titled 'When Phillip met Prince Philip: 60 years of The Duke of Edinburgh's Award' airs on ITV at 9pm on Monday (12.12.16).