The Boomtown Rats rocker recruited a host of stars including One Direction, Bono, Coldplay's Chris Martin and Ed Sheeran to record a new version of the Band Aid festive charity single Do They Know It's Christmas? to raise funds for countries affected by the Ebola virus.
The singers headed to a recording studio in London on Saturday (15Nov14), but Adele, who was reported to have been on the list of participants, did not turn up, and chief organiser Geldof now admits he tried to get her involved but she was not interested.
He tells Britain's Sun on Sunday newspaper, "Adele is doing nothing, she's not answering the phone... she's not writing. She's not recording. She doesn't want to be bothered by anyone. She won't pick up the phone to her manager. She's bringing up a family, you know.
"Some people just don't want to do it... of course they agree with it, but it's not their way of doing something..."
A spokesman for Adele tells the newspaper, "Bob and the organisers spoke directly with her management but at no point was she confirmed. Adele is supporting Oxfam's Ebola Appeal with a donation."
The singers assembled at Sarm Studios in Notting Hill, London to record their vocals and to make a similar music video to original 1984 version.
Geldof adds of the recording process, "The singers are just too f**king good to split up and say 'That's your line'... so we're getting them to do the track the way they want to. But it makes editing much harder."
The song will premiere during the broadcast of The X Factor U.K. on Sunday (16Nov14) and will be available to download from Monday (17Nov14).