X Factor guru Simon Cowell is of course old enough to be X Factor USA judge Demi Lovato’s dad, but it seems she hasn’t learned that lesson about being respectful to your elders…

During a recording of Conan O’Brien’s chat show yesterday, 20 year old Demi branded Simon “an ass*hole” after he called her “a brat”.

The whole interview then descended into a bitchfest as Simon had a dig at Demi’s dress sense, and she said he had no room to talk given his love of high-waisted pants and clingy T-shirts.

Click ‘Read more’ to see video clips of the war of words…

In other X Factor news, success story Olly Murs is now officially a millionaire, according to Stanley Entertainment.

But of course, though he’s without question done very well for himself – and is of course also a host on Xtra Factor – Olly is a ways behind One Direction, who, as we reported earlier, are worth around £100millon!

However, of Olly’s success, a source told the Sun, “Olly is a real grafter – has worked his socks off since he took part in The X Factor.

“He is constantly juggling working on the Xtra Factor, touring and recording new music, so every penny is hard earned.”

Earlier this year, Olly joked with a TV Biz reporter, “Am I a millionaire yet? That will hopefully come this year.

“The difference with me is that I am very conscious of my money and I look after it.”

Before he shot to fame on The X Factor, Olly worked in a call centre for £6 an hour.