Simon Cowell and Cheryl Cole

Simon Cowell and Cheryl Cole

Simon Cowell has allegedly snubbed Cheryl Cole's 30th birthday party.

The music mogul is said to have turned down the singer's invitation to join her in Los Angeles for her £50,000 birthday bash tonight (30.06.13), which she hoped would be the perfect opportunity to quash their long-standing feud.

A source told the Sunday People newspaper: "She sent an invitation to Simon as she genuinely wanted him there.

"He's been a big part of her life and, despite their falling out, she sees him as an old friend who she was very close to once. She was hoping he'd make it so is a little disappointed he won't be there.

"She has put all their differences aside and moved on in her life. The party is going to be one of the most memorable occasions and she carefully chose who she invited. Unfortunately though Simon wasn't able to make it."

The pair famously fell out when Simon dropped the singer as judge on 'The X Factor' USA, replacing her with Nicole Scherzinger, and Cheryl subsequently refused to rejoin the British version of the show.

The Girls Aloud beauty isn't the only star to have been angered by Simon of late, since it has also been reported new 'X Factor' USA mentor Kelly Rowland has been offended by his behaviour.

An insider told the Daily Star newspaper: "He snapped at her when she made a joke about him being late and she didn't appreciate that at all."

The TV tycoon allegedly drinks up to 20 cups of coffee a day, which is said to be making him ever "nastier" than usual.

The source added: "He guzzles it like water and all that caffeine is making him more hyper and nastier than ever."