Brian May and Nile Rodgers have recorded parts for the Grenfell Tower charity single.
The Queen guitarist and Chic legend are the latest to do their bit for the track, which was launched by musical mogul Simon Cowell, to benefit those affected by the horrific blaze at the west London block which was engulfed last week, killing over 70 and injuring many others.
Brian, 69, felt obliged to sign up as he spent most of his life living in the area.
Spice Girl Geri Horner, 44, is also on the song, which features the likes of Louis Tomlinson, Jessie J, The Who's Roger Daltrey and Pete Townshend, Rita Ora and Stormzy.
Robbie Williams witnessed Nile, 64, lay down his vocals at a studio session at west London's Sarm Studios on Monday (19.06.17) joined by Roger, 73, and One Direction star Louis, 25, and said the single is coming along "incredibly well".
The 'I Love My Life' hitmaker said: "It has gone incredibly well, obviously it's been a mental few days for everybody. It is buzzing in there, there's so much to be done."
'Pinball Wizard' guitarist Pete, 72, has also donated funds to four families who he knew who have lost everything in the fire, including a young girl from Spain who he bought a new piano after hers was melted in the blaze.
He told The Sun newspaper: "I've tried to help. I've written some cheques. I know four families who lived in the building.
"A mother lost her daughter, two little girls were in comas.
"A little Spanish girl studied the piano - they got a piano up 10 flights, but now of course it has gone now.
"I managed to get her a piano.
"My reaction the same as everybody else's.
"The families that have got away have the most trouble now and it's trouble for all of us."
Other contributors include Kelly Jones, John Newman and Emeli Sande.
Simon, 57, has praised the musicians for doing their bit and said the song, a cover of Simon & Garfunkel's 'Over Troubled Water', has already given him "chills".
He said: "It is unbelievable, I have chills. It sounds beautiful, absolutely beautiful.
"What they have done is remarkable, unbelievable. It is a very respectful tribute."
Simon says the "phone didn't stop" with artists wanting to join the all-star song and praised the British nation for always uniting when tragedy hits home.
He added: "All the artists have been unbelievable - that's the thing about this country, when things are s***, everybody comes around and you see good in people.
"Everyone has watched the news, it is horrific. The response we got was unbelievable. Everyone jumped in I got all these calls, the phone did not stop ringing all weekend."
The track is reportedly set to be released on Wednesday (21.06.17).
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