21/02/2012 02:35 GMT | Updated 21/02/2012 05:13 GMT

Simon Cowell's Quip Leaves Alesha Dixon Furious

The cracks are already beginning to show between Simon Cowell and his glamorous new protegee Alesha Dixon after he left the beauty speechless during a Britain's Got Talent audition by quipping, "Who are you?"

Simon was pleased as punch when he poached the former Mis-Teeq singer from the panel of Strictly Come Dancing, admitting it was a victory against what he sees as the nemesis of his string of TV talent shows.

Alesha, who was a judge on Strictly for three seasons after waltzing her way to victory on the show in 2007, was brought in as a glamorous new edition to the BGT judging desk, alongside funnyman David Walliams and original judge Amanda Holden.

But it Simon and Alesha have been rubbing each other up the wrong way. A war of words erupted when dance group Lil’ Diamondz - who won Dixon's kids' TV show Alesha’s Street Dance Stars in September - auditioned, with the star telling them that they "hadn't let her down".

The remark upset Simon, who growled, "What a silly comment to make. That’s a silly thing to say, Alesha. Sorry, who are you, anyway?”

The dig prompted the audience to boo the music mogul, and according to reports, Alesha was fuming over the comment.

A source told The Mirror: "Alesha obviously felt slighted. Everybody could tell because she clammed up and looked really embarrassed.

"Simon was reclining in his usual manner and didn’t seem bothered that he had just caused so much upset. Alesha was determined not to cause a scene in front of the audience but she really let rip behind closed doors.

"It was humiliating for Alesha that Simon suggested she is a nobody. This is especially the case when only a few months ago she was happily on another judging panel and Simon made it clear he wanted to poach her.

"She told her friends that she felt his dig had been ‘out of order’ and stormed off to her dressing room. She is not another Kelly Brook in this situation and knows that what she says on the panel is valid."

Model Kelly Brook was famously booted off the show in 2009 after a matter of days on the panel.

Watch out Alesha, remember what he did to his beloved Cheryl!