J.K. Rowling (WENN.COM file photo)

Celebrated author J.K. Rowling has promised young fans her next book will be for children, following the release of her debut adult novel last month.

The Harry Potter writer shocked critics with her first foray into the adult fiction market, The Casual Vacancy, which includes graphic descriptions of sex, drug-taking and self-harm.

However, the Brit is already working on a new project, which she insists will be family-friendly.

Appearing at the Cheltenham Literature Festival in England on Saturday, she said, "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,

"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 also told fans she often makes up bedtime stories for her three kids, adding, "They are tailored very much for my children, so don't expect to see those being published anytime soon."