The musicians donate tracks in aid of climate change and funds for disaster relief organisation
Cee-Lo Green for US X-Factor?
Cee-Lo reveals that he is in talks to appear as a judge on the US version of The X-Factor, but admits nothing has been confirmed yet.
Speaking to The Sun , the singer said: 'I had a meeting with Simon the other day and I was just offered a job.
'I didn't say no but I didn't say yes either.'
He added: 'I did mention to him that I am not a judge.
'I didn't feel fit to judge people, but I can make observations.'
Bruno Mars, JLS, Olly Murs, The Wanted, Cover Drive, Jessie J and Enrique Iglesias are just some of the stars to post messages on Twitter. Read them here.
The boys will be joined by Cee-Lo Green, Christina Aguilera and members of the Jackson family.
Cee-Lo Green and Amy Winehouse had plans to record a song together.