Sales of the new Band Aid single have been "manic" since its unveiling, organiser Bob Geldof has revealed.
The musician and campaigner admitted he had been "a bit nervous" but said the response had been "extraordinary".
"From what we've seen from iTunes it's gone bonkers," he told Radio 4's Today programme on Monday. "Within four or five minutes we had a million quid."
The single, which features Ed Sheeran and One Direction, topped the iTunes chart within an hour of going on sale.
A video for the song, re-recorded to raise money to tackle the Ebola crisis in West Africa, was shown on ITV's The X Factor on Sunday.
The track is now available to download at a cost of 99p. A CD version, costing £4, will be released in three weeks.
Also appearing on BBC Breakfast, Geldof said demand for the single had been "vast".
"We really can stop this... foul little plague," he continued, insisting that "100%" of proceeds would go towards the relief effort.
"I love living in this country at moments like this," he went on, saying the UK "led the world" in this form of charity campaigning.
The current outbreak of the deadly virus was first reported in March and has killed more than 5,000 people, almost all in West Africa.
Geldof and co-writer Midge Ure's first version of Do They Know It's Christmas? raised £8m for famine relief in Ethiopia.
Rita Ora, Ellie Goulding, Sam Smith and Coldplay's Chris Martin also attended the recording of the song on Saturday.
Geldof has also confirmed that chart-topping singer Adele did not respond to a request to take part.
"Adele won't pick up the phone to her manager," he said. "Some people just don't want to do it, some people say no.
"Adele, on the other hand, isn't engaged in rock and roll, pop music, not picking up the phone to anyone. Brilliant."
Further charity singles are also set to be recorded in the US, France and Germany, with Daft Punk and Carla Bruni among those said to be involved.
Geldof, however, was critical of Germany's response to the crisis, saying its leaders were not "doing enough" to tackle the epidemic.
"The most powerful economy in Europe are laggards and they shouldn't be," the 63-year-old told Radio 4's Sarah Montague.
"It's as dangerous for them as it is for us."