A member of the Queen Mother’s household at Clarence House, Moyra Smith, received the slice of the cake, which features the royal coat-of-arms, and protected it throughout the years with cling wrap, the BBC reported on Wednesday.
A collector bought the cake from Smith’s family in 2008, and it was put up for sale again this year.
The auction had started at 300 British Pounds, or roughly just over $400, and auctioneers assumed it would go for as much $700, the news outlet reported. Officials were shocked that it ended up going for 1,850 Pounds, or roughly $2,550.
Leeds, England, resident Gerry Layton won the bid and said he plans to go to Gloucestershire next week to pick up the royal prize. The cake has been included in his will to be donated to charity along with the rest of his estate, the BBC reported.
"I will have to think of a way to stop myself from trying to eat it though," Layton reportedly said.
The auction nearly coincided with the 40th wedding anniversary between Prince Charles and Diana on July 29, 1981. They divorced in 1996, and a year later Princess Diana died in a car accident in Paris.