X FACTOR host Dermot O’Leary has admitted training for his 24-hour dance marathon has been tough.

The former Colchester schoolboy will begin his moves at BBC Broadcasting House in London next Thursday, before finishing by dancing down Regent Street and into the London Palladium, where his efforts will be screened on live TV.

Dermot, 41, told Radio Times magazine he texted Comic Relief founder Richard Curtis with the idea for Red Nose Day, after dancing for six hours in Ibiza.

He said: “Initially, I thought it sounded like a lot of fun, but two weeks ago, reality set in and it started to sound like an endurance test.

“No one’s really done it before, so it’s hard to train for, but at the moment I’m doing a combination of running and dance lessons for about eight hours a week.

“I’m in a perpetual state of lactic acid coursing through my veins.

“I’m determined to keep moving non-stop – though I’ve requested lots of indie, shoe-gazing music to make sure I can slow it down a bit. And if I’m not actually dancing, I’ll be seat dancing.”

Mr Curtis said he was not impressed with O’Leary’s fundraising plan at first.

He said: “It’s a pretty well-established fact Dermot can’t really dance.

“He has one signature move, which he has performed at the start of the X Factor every week for the past eight years.”