Dermot O’Leary has admitted it’s going to be a “challenge” hosting The X Factor without Simon Cowell – and that he’ll miss judge Cheryl Cole.

The host told the Daily Mirror that it would be a “different show” without Mr Cowell and Ms Cole, who is favourite to land a job on the US X Factor.

He reportedly told the newspaper: “We will miss them. We will have to up our game now. It will be a different show. Whoever they bring in, no one can replicate Simon. There will only ever be one real Mr Nasty. He is a force of nature, he’s our boss.

“It will be a challenge not having Simon there week in, week out. Whenever I have a problem or a question, I go to him. Now I’ll have to figure it out for myself. We all have to work a little bit harder.

“I signed early but you have faith in the show – it’s the biggest in the country. I’d be the biggest idiot not to do it. It feels like home.” ITV recently confirmed that Mr Cowell would not have a weekly judging role when the UK version of the show returns in August. The first series of X Factor in the US is due to begin in September.

Mr O’Leary’s comments come as Mr Cowell said he thinks US viewers will take Ms Cole to their hearts on the US X Factor – and that bosses have been “desperate” to sign her.

Although the deal is yet to be finalised, Mr Cowell told Deadline he wanted her on the panel along with Paula Abdul.