Writing on website Pottermore, Rowling also details how she came about naming Uncle Vernon and Aunt Petunia.
Another million more copies being printed, says publisher.
Novel is fourth in the erotic franchise and was released on Christian Grey's birthday 18 June.
Police investigation launched amid fears stolen erotic novel will be sold on black market
Solo was depicted as married in the latest issue, taking place between A New Hope and The Empire Strikes Back.
Grey will be released on 18 June, Christian Grey's fictional birthday
Author wrote three of his famous chapters in the seven-bedroom, six-bathroom house.
Paulette Tavormina's meticulously arranged photos look like still life paintings by the Old Masters.
Controversial decision promoted a letter of protest and six writers to withdraw from the event.
Best-selling writer had published more than 60 novels in a career spanning 50 years.
Kennedy talks about his new book and how it focuses on the 'unknowingness of other people'.
Six writers will not attend 5 May gala after award for satirical magazine.
Employees have allegedly downloaded content illegally, in the form of an ebook on online piracy
Harry Potter-themed live action role play (Larp) cast its spell over more than a hundred would-be sorcerers.
Giuliana Rancic tells all in new memoir Going Off Script.
IBTimes UK interviews Robin Stevens, author of Murder Most Unladylike, on International Children's Book Day
Smoke and Shadow, the latest three-part comic series will focus on Fire Lord Zuko and Mai.
The world's largest collection of Harry Potter memorabilia has gone on display in Mexico City's Classic Toy Museum.
Campaigners say that the house is in urgent need of €1m of repairs to save it from ruin.
World Book Day, celebrated on 5 March, promotes a love of books and reading among children.
The Warner Bros. Studio Tour - The Making of Harry Potter, gave a preview of its expansion.
Project co-ordinator Claus Raasted hopes to create a permanent home for the magical college.
Edward Sheriff Curtis dedicated his life to photographing the lives of Native American people.
You won't recognise these people but you will know the images they are holding.
The film adaptation of Fifty Shades Of Grey will premiere at the Berlin Film Festival on 11 February.
BBC documentary explores whether author Charles Lutwidge Dodgson, pen name Lewis Carroll, was a paedophile
IBTimes UK looks at Winnie the Pooh author AA Milne's involvement in the First World War.
Ali Smith, Kate Saunders and Emma Healey among winners of prestigious book prize
A Tolkien fan gives his review of The Hobbit: The Battle of Five Armies
Harry Potter author JK Rowling to release exclusive new content every day at 1pm GMT until Christmas Eve eve.