Sales of Believe - which recently spent seven weeks at the top of the charts - reached 1.46m at the weekend, taking it above Dion's theme from the blockbuster movie.

The Canadian singer's single had been the biggest-selling of the year, notching up 1.42m on the back of the phenomenal interest in the film, which stars Kate Winslet and Leonardo DiCaprio.

But Cher's single is continuing to sell well - even though Irish girl group B*Witched knocked her from the number one spot on 13 December.

Believe is at number four in this week's Christmas chart - the biggest-selling week of the year for the record industry.

Chart expert Jason Legg from the HMV retail chain said: "It's almost the perfect pop record. It's also got the disco market covered, she's a huge gay icon and it's the sort of song that people can do the housework or wash the dishes to."

It also proves the enduring appeal of the 53-year-old singer - who had her first British chart hit 33 years ago.

Another chart record was set by soul veteran Isaac Hayes in his role as Chef, from adult cartoon South Park.

George Michael: On course for top-selling album

His suggestive hit Chocolate Salty Balls sold just 8,000 behind the Spice Girls' number one Goodbye - making it the biggest-selling number two song since 1984 on 372,000 sales.

George Michael's Ladies And Gentlemen: The Best Of... compilation sold more than 300,000 copies last week, the most ever sold over seven days by a double album. This breaks records set by Frankie Goes To Hollywood and Elton John.

The album is now the third-biggest-selling of the year, with only The Corrs' Talk On Corners and Robbie Williams' Life Thru' A Lens ahead of it.

HMV's Jason Legg said: "If George Michael continues to sell as well as he has been doing until the end of the year he looks likely to have the year's biggest-selling album - only 50 days after it was released."