Since we posted our story on Princess Beatrice's extraordinary Royal Wedding hat going on sale, the unique piece has hit the net and received a flurry of bids.

The extraordinary creation by Philip Treacy almost stole the show on Prince William and Kate Middleton's marriage day, and she has now put it on eBay. The description claims that 100% of the sale price will go to the Little Bee Initiative (headed by Princess Beatrice - 'Bea') which has been set up for the auction.

In this case the funds will then be split between UNICEF and Children in Crisis.

The description specifies that the hat is: "A unique sculptural celebratory headpiece in delicate tea rose silk, designed by one of the UK's most creative and influential milliners Philip Treacy.

"A truly individual, fun but elegant wedding bow becomes the fascinator form. This statement piece is worn on the front hairline secured by a clear wire headband that is easily disguised by the wearer's hair. This is a gravity defying hat!"

It gives the hat's dimensions as: Height - 29cm (at tallest point), width - 23cm (at widest point), depth - 9cm (not including headband) and a weight of 169g. It notes that the hat has been worn just once, for the wedding of the new Duke and Duchess of Cambridge.

There have been 46 bids at time of writing, reportedly including Dragon's Den TV show star Duncan Bannatyne who placed one of the earliest bids as the sale opened at £5,000 ($8,100), but that has already been doubled and the current bid is £11,300 ($18,300).

Princess Beatrice herself commented, "I've been amazed by the amount of attention the hat has attracted. It's a wonderful opportunity to raise as much money as possible for two fantastic charities. I hope whoever wins the auction has as much fun with the hat as I have."

The opportunity to acquire this unique piece of royal memorabilia - which must count as a strong investment - closes in six days and five hours' time on May 22.