Cowell: Duke called me a 'sponger'

The celebrity also claimed the Queen ignored him at the same event - the Royal Variety Performance in December 2007.

Cowell made the comments during an appearance on the American programme The Tonight Show with Jay Leno, but Buckingham Palace has strongly denied the accusations.

The pop svengali told the chatshow host: "It was actually embarrassing, I was on a show where she (the Queen) comes on (at) the end of the show and you have to stand around for hours.

"It is called the Royal Variety show, so she is in the audience. At the end, if you are involved in it, you have to stand around for hours and then say 'hello', and she ignored me and her husband called me a sponger."

Cowell told Leno: "I think he was trying to be rude. I just mumbled something and he walked off."

The encounter is mentioned by Piers Morgan in his latest book where he claims the Duke made the comment in reference to Britain's Got Talent winner Paul Potts who had sung that evening.

Speaking about Potts, who had signed to the X Factor judge's record label, Philip said to Cowell "you sponge off him then?".

Cowell was also photographed on the night smiling warmly at the Queen as the two shook hands.

A Buckingham Palace spokeswoman said: "The Duke of Edinburgh categorically did not call Mr Cowell a sponger. He has no reason to. He has said he does not know enough about Mr Cowell to make any sort of comment about him.