A previously unreleased duet between Johnny Cash and Ray Charles has been discovered.

The recording, of a Kris Kristofferson track called 'Why Me, Lord?' was made in 1981 with producer Billy Sherrill and located at a New York storage facility.

Valerie Ervin, the president of the Ray Charles Foundation found out about the existence of the recording after discovering correspondence between the pair referring to it.

In a letter to Ray, written in December 1981, Johnny wrote: "I hope you like this tape. I realise that the orchestration isn't big and I don't sing very good, but I think the thing has a feeling and a quality that the fans would really enjoy."

the song was recorded while Johnny was recording his album 'The Baron' and the recording features Johnny on lead vocals, and Ray on backing vocals.

In one of the letters he sent to Ray, Johnny suggests an equal split of the royalties. Although his response has been lost, Ray reportedly agreed.

The pair also recorded another song together, 'Crazy Old Soldier,' which was released on Ray Charles' 1984 album 'Friendship.'

It is, however, unknown why the song was never previously released. It will now be included on a collection of Charles' songs, titled 'Rare Genius: The Undiscovered Masters,' which was released on October 25 in the UK and October 26 in North America.