Big, brash and confident as ever, Simon Cowell said on Friday that his upcoming "The X Factor" would thrash the competition on U.S. television and topple "American Idol" as the nation's most-watched show.

Cowell, both executive producer and acid-tongued judge on the U.S. version of "The X Factor" called the singing contest a "game changer" and said it was "completely different" in style and content from his old vehicle "American Idol".

Asked whether he thought "X Factor", with its unprecedented $5 million cash prize for the winner, would beat "Idol" in the TV ratings when it debuts on Fox in September, Cowell told television journalists.

"If I didn't think we could -- and its not just 'Idol', it's any show -- we don't enter something for the silver medal. You do it because you want to be number one, and for the next few months we are going to throw everything at this to try and make it the best show on TV," the British producer said.

"I wouldn't have made the show unless I thought it would be different...we see this as a game changer," he added.

Fox, which broadcasts both talent shows, said it believed "X Factor" would reverse the network's historically "patchy" ratings in the fall TV season.

"If 'X Factor' can do half of what we hope it will do in the fall, Fox is going to be really difficult for the other guys to reckon with," Fox entertainment president Kevin Reilly said.

"X Factor" marks the return of the abrasive but popular Cowell to U.S. television after quitting "American Idol" in 2010 following 10 years in the judges' seat, and reunites him with his old "Idol" sparring partner Paula Abdul.

The new show debuts in a now-crowded market for TV talent contests that includes the surprise success of NBC newcomer "The Voice" earlier this year, and established favorites like "America's Got Talent" and a capella contest "The Sing-Off", as well as a revamped and resurgent "Idol" which airs from January-May.

"X Factor" welcomes contestants 13 years-old and up, as well as singing groups. It turns the judges into competing mentors and has contestants auditioning before vast stadium audiences.

"We will show the good bits, the bad bits, the ugly bits -- and there are a lot of ugly bits," Cowell said, saying there was room for more than two or three hit TV singing shows,

While the revamped "American Idol", with new judges Jennifer Lopez and Steven Tyler, increased audiences last season with a softer and kinder attitude towards its aspiring young stars, Cowell has clearly abandoned none of the sarcasm and biting wit that helped make him a star on U.S. TV.

Asked how it felt to be working again with Cowell, Abdul told reporters, "It's nice to be back in a demented relationship. It's like home."

"I think its more like 'The Exorcist 2'," retorted Cowell.

But he confessed that he had met his match in some of the younger contestants auditioning for a spot on the show.

"We have had to say to some of the 14-year-olds 'please be kind to me'...I was quite traumatized after some of the auditions." Cowell said that one young rapper had "absolutely chewed me apart. But I quite like that."

"The X Factor" arrives on Fox on Sept. 21 with a two-hour premiere, and ends with a two-part finale on Dec 21 and 22, where a winner will be chosen by public vote and scoop up a $5 million cash prize, as well as a recording contract with Cowell's Sony Music-owned record label SyCo.

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