Lots of Harry Potter fansites are reporting that the title of the sixth book has mistakenly been revealed.
It's claimed that one eager Potter fan was digging around on JK Rowling's website and discovered a note dated 1 July that may be written by the author.
It says that she's nearly finished the first draft and that it's called Harry Potter and the Pillar of Storgé.
There's been no official word from JK if that is the title, but Newsround's website is looking into it.
The fan claims to have got past this door on JK's site
Some sites also have a piece of video on them showing the fan accessing the secret bit of JK's website.
It looks very much like the other parts of the site, so if it isn't real it's a very good-looking fake.
The rest of the text does seem in the style of JK's writing, and she comments that she's struggling to keep the book shorter than the Order of the Phoenix.
We're trying to find out if the title is real or fake, so keep checking the site for updates.
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