Simon Cowell has destroyed the "integrity" of The X Factor by putting on novelty acts who lack talent, American Idol's Nigel Lythgoe has claimed.

Cowell, 51, quit his judging role on American Idol in May last year to launch The X Factor in the US this autumn.

But Lythgoe, American Idol's executive producer, told the Radio Times that viewers had not missed TV's so-called Mr Nasty.

He said: "In a way, I'm delighted Simon's left American Idol. He's given us the opportunity to refurbish it.

"Everyone said that it would be the end. And what's happened? The ratings are equal to last year's, we got 30 million votes the other evening, and if we lost 50% of our audience we would still be the number one show."

Cowell is taking The X Factor, with himself as judge and executive producer, to Fox TV with a record five million dollar (£3.09 million) recording contract for the winner of the series.

But Lythgoe, 61, said: "You have to choose contestants with talent - unless they have an incredible story to tell.

"I don't class The X Factor as a talent show. Look at (former contestants) Jedward and Wagner. They're on because we love the fun and the circus of it.

"Simon knows what he's doing - it certainly gives the press something to feed off. But it destroys the integrity of the show."

Lythgoe, who launched Cowell's career as a TV judge on Pop Idol, said American Idol hadn't suffered following Cowell's exit.

He told the magazine: "Does there always need to be a "nasty" judge? No, now that Simon's left American Idol we don't have a mean person and everyone's saying this is the best season since the early days."

Aerosmith frontman Steven Tyler, singer Jennifer Lopez and record producer Randy Jackson are this year's judges on American Idol, the biggest show in the US.

Record executive Antonio "LA" Reid, who helped launch the careers of chart stars Rihanna, Mariah Carey, Justin Bieber and Jay-Z, has been announced as one of the judges of the US X Factor.

The New York Post has reported that hip-hop star Nicki Minaj is in talks about joining Reid and Cowell on the judging panel.

Lythgoe returns this week as a judge on BBC1 Saturday evening show So You Think You Can Dance.