The music icon revealed the news ahead of Sunday's headline performance.
Band Aid 30's reworked version of 'Do They Know It's Christmas?' has premiered. Watch the video:
Sir Bob Geldof and Midge Ure once again assembled an all-star lineup for the song, which will raise money to combat the Ebola crisis in western Africa.
Speaking on TV ‘s The X Factor, Geldof said; “We can stop it, and we will stop it, and we will support those immensely brave 1,000 NHS workers, those young doctors and nurses who are going down there, those young soldiers... and the governments who are leading the world on this," he said.
One Direction, Ed Sheeran and Rita Ora open the track, which also features Paloma Faith and Guy Garvey of Elbow.
The new version of 'Do They Know It's Christmas?' also includes updated lyrics to reflect the devastation caused by the disease.
'Do They Know It's Christmas?' is priced at 99p for a digital download. The CD version is priced at £4.
Band Aid 30 Lyrics
It's Christmas time, and there's no need to be afraid
At Christmas time, we let in light and banish shade
And in our world of plenty, we can spread a smile of joy
Throw your arms around the world
At Christmas time
But say a prayer, pray for the other ones
At Christmas time, it's hard but while you're having fun
There's a world outside your window, and it's a world of dread and fear
Where a kiss of love can kill you, and there's death in every tear
And the Christmas bells that ring there are the clanging chimes of doom
Well tonight we're reaching out and touching you
No peace and joy this Christmas in West Africa
The only hope they'll have is being alive
Where to comfort is to fear
Where to touch is to be scared
How can they know it's Christmas time at all
Here's to you
Raise a glass to everyone
And here's to them
And all their years to come
Let them know it's Christmas time after all
Feed the world, let them know it's Christmas time again
Feel the world, let them know it's Christmas time again
Heal the world, let them know it's Christmas time again