Leona Lewis knocked off the top spot by Katie Melua and Eva Cassidy

Leona Lewis' 'Bleeding Love' was knocked off the top spot today by Katie Melua and the late Eva Cassidy, with their version of the classic Louis Armstrong song "What a Wonderful World".

Their charity duet Leona's single from the number one spot after seven weeks, according to the Official UK Charts Company.

Cassidy, who died of cancer in 1996, is Melua's musical idol. Money raised by their duet goes to the British Red Cross.

Bookmaker William Hill said the song is its third favourite to secure the Christmas number one, behind this year's "X Factor" winner Leon Jackson and Lewis, Reuters reports.

The UK's official Top Ten Singles are as follows:

1. Eva Cassidy & Katie Melua -What A Wonderful World.

2. Leona Lewis - Bleeding Love.

3. Soulja Boy Tellem Crank That (soulja Boy).

4. Mariah Carey - All I Want For Christmas Is You.

5. Girls Aloud - Call The Shots.

6. Timbaland Pts Onerepublic - Apologize.

7. Take That - Rule The World.

8. Pogues Ft Kirsty Maccoll - Fairytale Of New York.

9. T2 Ft Jodie Aysha - Heartbroken.

10. Cascada - What Hurts The Most (All Around The World).