Worldwide advance orders for the new Harry Potter book have exceeded one million, says online retailer Amazon.
Posters announce the imminent arrival of the new Harry Potter book
At this rate, pre-orders should top the 1.3 million pre-orders received for the previous Harry Potter book in 2003.
Amazon's UK arm has already taken more than 200,000 pre-orders of Harry Potter and the Half-Blood Prince, published in the US and UK on 16 July.
Last week US chain Barnes and Noble said advance orders had topped 750,000 and were expected to exceed a million.
"Amazon customers are clearly incredibly excited about the sixth Harry Potter book," said Kes Nielsen, senior vendor relations manager at Amazon.co.uk.
However, some smaller bookshops claim their sales will suffer due to the huge discounts Amazon and other retailers are offering on the latest instalment of JK Rowling's boy wizard saga.
The Half-Blood Prince topped Amazon.co.uk's book chart less than 24 hours after its release date was announced last December.
The children's and adult versions of the title have remained in the top two spots ever since.
The book will be published simultaneously in the UK, the US, Canada, Australia, New Zealand and South Africa.
The Potter book series has inspired three hit movies, with a fourth - Harry Potter and the Goblet of Fire - due to be released on 18 November.