Cowell: I don't want to be on 'Idol' if it's not No. 1

American Idol judge Simon Cowell says he will leave the most popular show on television if it ever slips from the top spot in the ratings.

“The idea that for the next five years, I’d be doing exactly what I’ve been doing for the past five years … the thought is just too depressing,” Cowell said in a recent interview in his trailer awaiting a taping of Idol at CBS Television City. “I’d go nuts, bored out of my mind. You have to evolve, you have to change. I like the challenge of launching something new.”

With Cowell’s deal with Fox expiring at the end of next season, that “something new” could be a U.S. version of his UK  singing competition series The X Factor. Any doubts about Cowell’s role in the success of Idol disappeared when he launched Factor three years ago -- the somewhat similarly formatted show became a massive hit that has since supplanted American Idol predecessor Pop Idol.

The Factor success was worrisome enough for Fox to forbid Cowell from launching the show in the U.S. as part of his current Idol deal. But all that could soon change. Between Idol’s continuing popularity and his ownership of Factor, Cowell is armed with both a carrot and a stick.

Asked if he would want to stay on Idol if the series ever slipped from No. 1 in the Nielsens, Cowell burst out laughing at the apparent obviousness of the answer.

“Absolutely not!” he said, looking horrified. “It's like running in the 100 meters and saying 'I came in fifth' -- then why bother? Being No. 1 is verging on an obsession with me. I don’t like being No. 2. I don’t mind when you start at No. 10 -- people don’t always go on as No. 1 -- and you’ve got somewhere to go. But if you’re at the point you’ve reached it, of course you want to stay there."

Though the Idol audience has declined over the past few seasons, it remains far and away the biggest Nielsen needle-mover with about 22 million viewers per episode. No other TV program approaches its popularity.

Yet unlike many in the TV business, Cowell rejects the claim that Idol ratings erosion is inevitable.

“I don’t accept the argument of fragmentation or declining numbers,” he said. “The Super Bowl goes up every year.”

Factor, he noted, has also grown its audience every year, which suggested to Cowell that America is ready for another music competition series.

“We have to bring in another music show,” he said. “In the U.K., there is more than one type of music show running throughout the year. And I think the same thing could happen here, because for the fall, nothing really happens. It’s something we’ve been thinking about … I would definitely do it now.”

“Maybe it’ll be X Factor, ” he teased vaguely. “Maybe it’ll be something new …”

See the rest of Cowell’s interview as part of The Hollywood Reporter’s second annual Reality Power List publishing on April 30.