The magenta silk gown has spent the last 31 years wrapped in plastic in the unnamed Sydney, Australia-based woman's wardrobe.

A longtime friend of Elton's, she kept the dress as a keepsake, but has now been passed to Harley Medcalf, who helped organise the rock star's Darling Point, Sydney wedding to his one-time sound engineer, with a view to him auctioning off the gown.

All proceeds from the sale will benefit the MCGrath Foundation charity.

Medcalf tells the Sydney Daily Telegraph, "I know the lady, we went to the wedding together and it was probably the party of the year. It (gown) would be worth a lot to someone. It’s certainly a valuable piece of memorabilia. It’s a size 10 to 12, kept in very good condition."

Elton and Renate were married for four years before they parted ways. Shortly after the marriage ended, the Rocket Man singer 'came out' as a gay man.

He wed his longtime partner David Furnish in December (14).