Sam Smith recorded the single in Los Angeles with John Legend earlier this year.
They will perform the ballad during Comic Relief: Face the Funny on Friday, March 13, on BBC One.
The one-off performance will be broadcast live from the London Palladium.
A digital download of the special track has been released ahead of their performance.
Sam Smith said: “Lay Me Down holds a very special place in my heart.
“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.”
John Legend said: “Sam is such a talented artist. We’ve been looking forward to working together for a while now.
“I’m so glad we could collaborate on such a great song and for such a great cause.”
All the profits from the sale of Lay Me Down will go to Comic Relief.
lvJX7OgPYwwImage source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…