The 1981 wedding of Prince Charles and Princess Diana (opens in new tab) has been called the "wedding of the century," and for good reason. The event redefined the term "lavish affair" and cost a whopping $48 million (opens in new tab) (the equivalent of over $143 million today, adjusted for inflation).

Charles and Diana's wedding (open in new tab) was not just a cultural event, but also a moment that will go down forever in royal history (open in new tab). The couple's wedding cake was to be auctioned off, as a slice of the couple's wedding cake was to be auctioned off.

Yes, you read that correctly. A piece of Prince Charles and Princess Diana's (open in new tab) 40-year-old wedding cake still remains and will soon be auctioned off to the highest bidder. Who had leftovers from the royal wedding for 40 years?

Well, that who is Moira Smith, who was working for the Queen Mother at Clarence House (opens in new tab) at the time of the Royal Wedding. According to auctioneer Dominic Winter (open in new tab), the staff at Clarence House (open in new tab) were sent one of the 23 royal wedding cakes commissioned for the occasion.

"In addition to the main official five-tier wedding cake, 22 wedding cakes were supplied by various manufacturers, which appear to have been sent to Clarence House for the Dowager Queen's staff to eat," the slice description (opens in new tab) explains.

"Based on its size, it is most likely either the side of the cake or the top of a single-tier cake.

As for the "how" question, Smith preserved the cake with plastic wrap and aluminum foil in exactly the same way we preserve leftovers.

"It appears to be in exactly the same good condition as when it was originally sold, but we recommend not eating it," Dominique Winter explains in the description, answering the question that everyone is obviously thinking.

The 28-ounce slice, which measures 8 inches by 7 inches and features the royal coat of arms in blue, gold, and red, will be auctioned off on August 11 and is expected to sell for about 500 pounds (almost $700). And you can bid online from anywhere in the world (opens in new tab).