Tickets for the Diana Concert sold out in within minutes today.
"The initial allocation of tickets has now been sold and we hope more tickets will be available at a later date," said a spokeswoman for the William and Harry.
She added that around 22,500 tickets were sold in 20 minutes, and that the capacity for the event was likely to be about 60,000. More tickets may go on sale at a later date via the event's Web site www.concertfordiana.com.
The face value of tickets is 45 pounds ($89) each, although they attracted bids of up to 500 pounds each on eBay's UK site early on Wednesday.
EBay, which has been criticised in the past when tickets to charity concerts have appeared on its site, later promised to remove them as soon as possible "as a mark of respect for the memory of the late Diana."
While a number of acts have been announced, there are more to come.
William and Harry explained they had released just "a flavour" of those confirmed.
One of them, Sir Elton, said: "I applaud Princes William and Harry for choosing to honour their mother with this concert. I am absolutely thrilled to be performing at this great event.
"Diana was a personal friend and someone I greatly admired for her tireless and enthusiastic work for charity."
It is possible that the entertainer will perform his revised version of Candle in The Wind, sung at Diana's funeral. If so, this would only be because her sons requested it.
Simon Le Bon of Duran Duran added: "The concert next summer seems an entirely fitting way to celebrate her life and her work.
"We are honoured that she always referred to Duran Duran as her favourite band as she was certainly our favourite princess."
Proceeds from the show will go to a number of charities that were supported by the princess during her life, and to two of her sons' own charities, Centrepoint and Sentebale.