(Cover) - EN Showbiz - Simon Cowell was constantly naughty when he was at school.

The music mogul has gained a reputation for his scathing remarks on television talent shows such as American Idol and The X Factor. Simon has now left the American Idol judging panel and is focusing on taking a new version of The X Factor to the US.

Despite his career success, the star admits he had no idea what he wanted to do when he left school and was a hugely disruptive influence in class.

"I was bored, constantly naughty, always doing things I shouldn't be doing, he revealed in an interview with Oprah Winfrey for her new television show Oprah Presents Master Class. And I never had a clue as to what I was going to do - other than I promised myself whatever I did do, I was going to have fun."

The 51-year-old British star has no regrets about his career so far and although he enjoyed his time on American Idol he feels ready for a new challenge. Simon has revealed a piece of advice he was given a few years ago motivates him to constantly move forward. He insists he does his best to remain grounded and never takes his work for granted.

"Simon, always know when to leave the fair, he explained when asked what advice has helped him carve out a career. I can look back on the last ten years and say it's been a blast. I've enjoyed myself. It's not the most difficult job in the world, is it? 'You're good, you're terrible,' walk out." (C) Cover Media