The Philip Treacy design, described on auction site eBay as being made of “delicate tea rose silk”, has been sold to raise money for two charities nominated by the princess, Unicef and Children in Crisis.
It caught the attention of commentators as Prince William and Kate Middleton tied the knot on 29 April, with its unusual structure compared to a toilet seat, a cat flap and a Turkey Twizzler.
Prince Beatrice said: “I’ve been amazed by the amount of attention the hat has attracted.
“I hope whoever wins the auction has as much fun with the hat as I have.”
The description on the auction site calls the hat a “unique sculptural celebratory headpiece”.
Treacy himself said he had been “surprised by the overwhelming response” to his creation.
Get the look for less – see below for the Channel 4 News origami version