Simon Cowell heads out told Oprah Winfrey that he'd grown as much as he could with "American Idol," and he'd always wanted to leave before he would be asked to.

Simon is bringing the “X Factor” to American, and yes, it will be in competition with “Idol.”

Cowell admits, " 'Idol' is our competition, but so is everything, [like] ‘Dancing with the Stars’ …everything that’s popular. 'X Factor' will be a standout “because there’s no upper-age limit.

“We thought it could be like David vs. Goliath, where a 16-year-old could be competing against a 35-year-old. I have no idea if it’ll succeed, but I’ll boil it down to whether or not we can find a star, and I’m confident that we can find a star.”

Simon Suffers From Depression And Can Get 'Very Dark'
 
Simon Cowell can't control the deep depression he often falls into, and it's best to leave him alone in his darker moments.

He told Oprah, "When I'm like that I kind of feel like going into some slight hibernation. I'm very dark when I'm in those moments... I get very, very down. Don't come near me. (I'm) like a bear in a cage."

Asked what he has to get down about, Simon said, "Maybe it's the draining effect when you have a lot of people who depend on you... by the end of it you feel that everything's been sucked out of you because of that dependency."

But he'll never take anti-depressants.

He adds, "I would never take a pill, for instance, to deal with that. It's something I've got to deal with myself.

"I put it down to, 'OK, so I'm a bit moody, bit over-dramatic about everything, give yourself a mental slap and get on with it.'"

 You must click on the audio to find out what he says about why he's leaving American Idol and who should replace him!!