American Idol judge Simon Cowell says the hit reality TV show "will flourish" with or without him.

"Whether I'm on it or off it, I think the show will flourish without me. I genuinely do," he told USA Today, ahead of the ninth season of American Idol.

Speculation over his future on the show followed his announcement that he will take rival British reality show The X Factor to the US next year.

"I really don't know until I hear it from him," said co-star Randy Jackson.

"The rumours get so wild and crazy, you just don't know what to believe," said fellow judge Jackson.

"It is pretty much a distraction," he added. "Let's focus on what we are judging... finding that next superstar talent."