In honor of Red Nose Day, the duo recorded a more upbeat version of Sam's "Lay Me Down," releasing a music video which showed them singing in a studio juxtaposed with clips of children and families in Africa.
John and Sam, who recorded the ballad earlier this year, will perform it during Comic Relief: Face the Funny Friday on BBC One at the London Palladium.
"Lay Me Down holds a very special place in my heart," Sam told the BBC. "Not only did I perform it at the Brits, I'm now going to perform it live on the Red Nose Day show with the extremely talented John Legend."
"I recently visited a Comic Relief-funded project in my hometown which supports the young LGBT community in London. I'm extremely proud that my single will help raise money for projects like this and many others in the UK and across Africa.
All profits from the sale of the single will go to Comic Relief, an organization raising money for Red Nose Day (Friday). On that day, people around the world do something funny for money, with the proceeds going towards those "living tough lives" across the UK and Africa.