Prince Harry 's bombshell book has become the UK's biggest selling memoir ever in its first week of publication.
Spare has sold 750,000 copies across all formats - hardback, audio and eBook - since it was released on January 10.
Nearly 470,000 were purchased in print alone, which is worth around £6.6million in UK sales, according to official figures from Nielsen BookScan.
Nielsen, Guinness World Records and Waterstones further confirmed that it is the fastest-selling nonfiction book since UK records began in 1998.
It has also become the sixth fastest-selling book of all time, following behind four Harry Potter books and Dan Brown's The Lost Symbol.
Tom Tivnan, Managing Editor of The Bookseller, told The Mirror: "It's a phenomenal number, and probably a lot more than the publisher would have dreamed of really.
"Non-fiction doesn't really sell in these numbers normally. 250,000 copies would be an amazing goal in the first week, but 470,000 is historic. It's the fastest selling non-fiction, adult hardback book of all time.
"I think the publishers are probably deliriously happy. It's an amazing number for the first week but they paid a big advance. We'll see if sales keep coming - I expect they will."
Mr Tivnan also revealed that the massive figures could encourage Prince Harry to write more books.
He said: "I believe Harry does have a four-book deal, but it is shrouded in secrecy. That's what's rumoured.
"I don't know if he'll do something like this again - a memoir so personal - but probably something very worthy and princely, let's say.
"The sales will give the publisher something to think about, and maybe they'll follow up harder for a second book."
The Duke sparked headlines for days due to claims he was attacked by his brother the Prince of Wales, he killed 25 Taliban members during the Afghanistan war and took illegal drugs.
But although many extracts were leaked from the book ahead of its official publication, Mr Tivnan doubts this would have had much of a negative impact.
He said: "Bits that had leaked and prior appearances helped to wet the public's appetite. The Netflix documentary also helped.
"If tonnes of excerpts were released prior to publication then it could've hurt sales, but I think the Sussexes' narrative was that you have to read it in context, rather than from tabloids picking and choosing, and that probably helped as well."
He also debunked speculation over a lack of appetite for the book after it was slashed to half price in its first week of UK sales.
Mr Tivnan said: "Any big hardback title in first few weeks of sales will be half price generally at places like WHSmith and Amazon.
"The average selling price is £14, but that's something to be expected. The second best selling book of the week is a cookery book which is half price too."
He added: "The bottom line is that I think it's a really good result of the publisher.
"They were selling a big celebrity book in January, which is a massive gamble because it's normally the time for cookery and diet books in the New Year, so I think they're probably quite happy with how it's gone."
According to the publisher, the English language edition of Spare sold more than 1,430,000 units in all formats and editions in the United States, Canada and the UK when it first hit bookshop shelves.
And announcing the latest record sales, Larry Finlay, Managing Director of Transworld Penguin Random House, said: "We announced last week that SPARE was the fastest selling non-fiction book ever on its first day of publication, a record that has been confirmed by Guinness World Records.
"We now know that it is also the biggest selling memoir ever in its first week of publication."
