J K Rowling is still writing Harry Potter and the Half-Blood Prince, but a slight change to her website has been causing lots of speculation.
She's changed a line that said her site was a place "where I can announce I've finished Book Six, and no, that's not going to happen very soon".
It's now been altered to say Book Seven, instead of Book Six.
That's led fans to wonder if Book Six isn't far away, but her agents say: "The book is not yet finished."
Her agency manages relations between her and her different publishers, and they would be the first people to be told when the book is completed.
The last book was announced on 2003
They also help co-ordinate the process in the run up to an announcement.
The last big one was, of course, for Harry Potter and the Order of the Phoenix.
Book Five was finished and delivered in December 2002, and then read by a tiny number of people at her main publishers.
And then on 15 January 2003 fans first learnt that the book had been completed and that it would be released in June 2003.
Now that J K Rowling's official site is up and running, fans are advised to be patient and wait for more updates there straight from JK herself.