Simon Cowell apologises after swearing on 'The X Factor UK'

Los Angeles: Music mogul Simon Cowell has apologised to the contestants of "The X Factor UK" for swearing on the reality TV show.

Cowell, 55, was jeered by the crowd as he showed his displeasure at being given the notoriously tricky category of mentoring the Over 25s category in this year's X Factor, reported Daily Mirror.

"For f--ks sake," he blurted out before walking over to the hosts. "Are you winding me up? Are you sure this is the right name in there? Can I have a look?"

Shortly after the episode aired, Cowell spoke out on Twitter about his word choice.

"Sorry for swearing on the show tonight. It's not big and it's not clever... Yes I did apologise to my contestants."

The judges and categories were paired up by fans of the show for the first time ever this year, who voted via the social networking site.

Cheryl Fernandez-Versini will oversee the Groups, while new judges Nick Grimshaw will mentor the Boys and Rita Ora will look after the Girls.