More than 72,000 copies of the new Band Aid single were sold on its first day of release, according to sales figures.
A Band Aid spokesman said they were 'very, very happy' with the demand reports BBC online.
Dido, Robbie Williams and Chris Martin are on the new single, which is raising money to fight hunger in Africa.
Estimates of how many copies the 2004 version of Do They Know It's Christmas? could sell by the end of the first week range from 250,000 to 600,000.
If it sold 500,000 copies, more than £1m would be raised for charity. The CD is being sold for £3.99, with HMV, Virgin and Woolworths donating their profits.
HMV spokesman Gennaro Castaldo said: 'I think the single will continue to sell steadily in large quantities over the coming weeks to nudge it towards the million mark, which would be a fantastic achievement.'
Between £2.15-£2.95 from each single goes to the Band Aid Trust charity, depending on where it is bought, the Band Aid spokesman said. That includes 70p that would have gone to the government as VAT, which Chancellor Gordon Brown has promised to refund.
The original version, which featured stars including George Michael, Phil Collins and Duran Duran, sold 750,000 copies in its first week and 3.5 million in total.
That made it the UK's biggest-selling single and it has only been surpassed by Sir Elton John's tribute to Princess Diana, Candle in the Wind '97.
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