Adele turned down Sir Bob Geldof's offer to record a track for Band Aid 30, he says.
The Rolling in the Deep singer was approached by the Boomtown Rats rocker to take part in Saturday's star-studded recording session, aiming to raise funds to fight the Ebola outbreak in West Africa with a new release called Do They Know It's Christmas.
But he says he couldn't get her to join the line-up.
"I got through to someone, not her, but she's not doing anything at all at the moment. It's fine, I understand it's not for everybody and other people support in different ways," he told UK newspaper The Mirror.
The line-up Saturday included One Direction, Chris Martin and Ed Sheeran, among others, all meeting at a London studio to record the track.
Bob joined the singers, offering them a few words of inspiration.
"Today you join Ray Charles, Miles Davis, Michael Jackson, Stevie Wonder, Pink Floyd and all those other people who at one time have done something for Band Aid," he told them.
The musician believes his words resonated, and told the outlet he's more than pleased with how the recording session went.
"That pulls them back to say, 'How did I get here?.' They think, Jesus I've got to do this now, but this is the thing that rallies the country and that helps to stop this filthy disease," he said, heaping praise specifically on boyband 1D.
"One Direction nailed it. They sound great," Bob gushed. "It's a very moody track this time. The producer, Paul Hepworth, said to them try and whisper into it and they had never whispered so much, but they were really good."
Adele's spokesperson had not immediately commented on the claims.