A heavily revamped "American Idol" returns for a 10th season on Wednesday hoping to regain its mojo after losing audiences and its biggest star.

Airing for the first time without sharp-tongued British judge Simon Cowell, the TV singing contest has ramped up the star power with new judges Jennifer Lopez and rocker Steven Tyler in a bid to maintain its place as the dominant force on U.S. television.

And producers say they are putting new emphasis on supporting and mentoring contestants in the hope of finding the next Kelly Clarkson or Carrie Underwood -- the only two winners to have enjoyed strong careers.

"I'm not going in there to be a harsh judge or an overbearing judge," said Aerosmith frontman Tyler. "I made some harsh comments the first week (of nationwide auditions) ... I only did two of those because I didn't want that to happen again."

Executive producer Nigel Lythgoe, returning to the show after a two-year absence, said the new panel would "bring more of a critique rather than just 'pack your suitcase, go home',".

"American Idol" has lost about six million viewers over the past four years, and recent winners Kris Allen and Lee DeWyze seem destined to slip into obscurity after suffering dismal sales for their debut albums.

But Todd Gold, executive editor of Xfinity TV, said buzz was strong after a summer of upheavals that also saw the exits of judges Ellen DeGeneres and Kara DioGuardi, and a switch to record label Universal Music from Sony Music Entertainment.