The eagerly awaited novel will be published by Little, Brown, a division of French company Hachette Livre. Her Harry Potter series is published by Bloomsbury, the publishing house which spotted her gift after many rejections and is now are planning celebratory 15th anniversary editions of Harry Potter and the Philosopher's Stone in June.
Unfortunately for her fans, JK and her publisher are both keeping mum on the book's details – so much so that we can't even tell you the genre - but JK says she's entering a "new phase" of writing, and will announce further details later this year. The author is worth an estimated £530 million.
"Although I've enjoyed writing it every bit as much, my next book will be very different to the Harry Potter series ... the freedom to explore new territory is a gift that Harry's success has brought me, and with that new territory it seemed a logical progression to have a new publisher.
"I am delighted to have a second publishing home in Little, Brown, and a publishing team that will be a great partner in this new phase of my writing life."
The news has already sparked excitement from JK's army of loyal fans, with her name trending on Twitter this afternoon.
- The Harry Potter series has sold over 400 million copies.
- The final book, Harry Potter and the Deathly Hallows, sold 11 million copies on the first day of its release.
- The Harry Potter books are distributed in over 200 territories and are translated into 69 languages.
- The last four Harry Potter books consecutively set records as the fastest-selling books in history.