The 34-year-old slice of fruitcake with cream cheese frosting, which is said to be in “very good condition” despite its age, was baked by David Avery, the head baker of the Naval Armed Forces.
The cake is being auctioned in Los Angeles in its original packaging, which includes a gift card reading: “With best wishes from Their Royal Highnesses The Prince & Princess of Wales”.
It also comes with a distinctive white and silver presentation box, which is adorned with the Prince of Wales’ feathers and a monogram of the couple’s initials.
The box is marked “Buckingham Palace”, and bears the date of the wedding: 29 July 1981.
Presentation box: the cake is said to be in “very good condition”
The auction will be conducted by Nate D. Sanders, which has started the bidding at $1,100 (£726).
However, pieces of the wedding cake have previously sold for much more, with a slice going for $1,375 (£909) in 2014