An unreleased demo tape of Paul McCartney and Ringo Starr's only jointly written duet is expected to fetch $24,900 at auction.
The track Angel in Disguise was recorded for Starr's 1992 solo album Time Takes Time but did not make the cut.
However, a cassette containing two versions – one with McCartney on vocals and another with Starr singing – found its way to former Radio Luxembourg DJ Tony Prince, who was asked to find artists to record it as a cover.
Prince's collection of music memorabilia is to be sold by Cheshire, England's Omega Auctions in a sale starting on 19 May, with the tape expected to cost bidders around $24,900.
The auction house's Paul Fairweather tells British newspaper The Times the "track certainly had enough about it to be included in the album," and adds: "It's fantastic to be able to bring to the market a previously unheard and unreleased track. I am sure if Paul was to release this himself it would certainly prove a hit with fans."
The two surviving members of The Beatles have collaborated on several songs in recent years but staff at Omega Auctions say it is thought that Angel in Disguise is the only song "co-written exclusively" by the duo without any other musician's involvement.
