The Harry Potter author, who released her first adult novel The Casual Vacancy last month, said she has nearly completed work on the new project.
"As the writer of Harry Potter, I'm always nervous of committing myself to another children's book, but yes, the next thing I write will be for children," she told The Daily Telegraph.
"I have a lot of things on my laptop currently, including a couple of things for children - for a slightly younger age group than Harry Potter was aimed at - which are nearly done and will, I think, be the next thing I publish.
"I have run them by my children and they seem to like them which is always a good sign. I also have some ideas for another book for adults but it isn't too far on [in development]."
Rowling recently revealed that she is tempted to write a 'director's cut' of the Harry Potter novels.
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