British pop sensation Sam Smith has recorded a special version of his single Lay Me Down with John Legend for Comic Relief.

The Brit Award winner recorded the single in Los Angeles with American-born Legend earlier this year.

They will perform the ballad on 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 was released on iTunes today and the single can be bought at Sainsbury's.

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, which is so exciting.

"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."

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."

The single is produced by Jimmy Napes and Steve Fitzmaurice and was written by Sam Smith, James Napier and Elvin Smith.

Universal said it will donate all profits from the sale of the single to Comic Relief.