Kelly Clarkson, the former waitress who shot to fame as winner of the American Idol TV talent contest, has scored the highest-selling single of any new release for three years.

Clarkson's debut, A Moment Like This, sold 236,000 copies in its first week on full release to take it to number one in the United States chart.

"We're in uncharted territory," said Geoff Mayfield, director of charts for Billboard magazine, which publishes the Hot 100 list.

Some 23 million watched the US Idol final

Clarkson's chart success follows the pattern set by the UK's Pop Idol when winner Will Young broke records with his debut.

American Idol became the summer's biggest TV hit in the US, with 23 million people watching the final.

Clarkson's single was rushed to shops in less than two weeks.

"This is the first one to sell more than 200,000 [in a week] since 1999, so those are pretty big accomplishments," Mr Mayfield said.

The ballad has been compared to the emotional style of Whitney Houston and Mariah Carey.

Will Young's debut sold 1.1 million in its first week

Lyrically, the song refers to Clarkson's rise from cocktail waitress to pop's newest superstar.

It knocked rapper Nelly off the top spot after he had spent seven weeks at number one with Dilemma.

Clarkson, 20, from Burleson, Texas, was signed up by British pop svengali Simon Fuller, who created the Pop Idol format.

Another Fuller charge, Will Young, sold more than 1.1 million copies of his debut single in the UK just after his victory in March.

And Fuller appears set for a double success with number one hits on both sides of the Atlantic.

Young and UK runner-up Gareth Gates look certain to hit the top spot in the UK on Sunday with their cover of the Beatles' The Long and Winding Road.

But pundits have said the standard of the US finalists was better than that of their UK counterparts.

A compilation album featuring the American Idol contestants is released on 1 October, while a tour with all 10 finalists begins the following week.

But the release of Clarkson's album has been put back from November to 2003.