A piece of toast believed to have come from Prince Charles' breakfast plate on the day he married Princess Diana is to be auctioned off in the U.K. later this month, the BBC reports.

According to the Derby Telegraph, 83-year-old Rosemarie Smith took the slice from Prince Charles' tray on July 29, 1981, the day of the royal wedding. Smith was visiting her daughter, once a maid at Buckingham Palace.

"I was with her in the corridor and saw Prince Charles had left some toast on the tray. I had been thinking about a keepsake from the wedding and saw the toast and thought to myself: Why not?," Smith told the BBC.

Since then, the toast remained well preserved after Smith stored it in a Royal Crown Derby cup.

Auctioneers believe the 31-year-old toast could fetch as much as $775 (£500) when auctioned in Derbyshire, England on Thursday July 19, reports ITV News.

"When the slice was brought in, my first reaction, to coin a phrase, was, 'Crumbs!' We hope collectors will appreciate this bygone of royalist history," Auctioneer Charles Hanson said, according to the Daily Mail.

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