Simon Cowell rushed to hospital after collapse

X Factor boss Simon Cowell. Photo / Supplied

Simon Cowell was rushed to hospital after fainting and falling down stairs at his London home on Friday morning, but he's reassured fans he is on the mend.

He said: "I fainted and fell down the stairs. I've got a bit of concussion. I feel better now."

Asked if he had a message for worried fans waiting outside his house, he added: "Thank you."

However, Simon - who was at home with his young son Eric, three, when he fell - admitted he is unsure whether he will be well enough to appear on 'The X Factor' on Saturday night's first live show of the series.

He told the Mirror Online: "I will be back but I don't know about tomorrow."

It was previously explained the 58-year-old music mogul had fallen at around 6.45am while going to get a cup of hot milk to help him sleep.

A source said: "It's been a scary morning. It was very early and Simon was going down his stairs to get some hot milk because he couldn't sleep. He fainted and is thought to have fallen down the stairs. An ambulance was called and he was stretchered out of the house in a neck brace surrounded by worried aides."

Simon's girlfriend, Lauren Silverman, is believed to be making her way back to London from New York following his accident.

Earlier this year, the outspoken TV personality was forced to pull out of 'X Factor's London auditions due to a mystery illness.

And in June, Simon - who is a self-confessed workaholic - missed his own charity ball after he was struck down by flu.