This is exciting news for Harry Potter fans! J.K. Rowling has announced that she is writing a new children's book. 

The author revealed the news during her first interview as her pseudonym Robert Galbraith on Radio 2 Book Club. 

"I have an idea for a children's book, actually I have written part of a children's book that I really love, so I'm definitely going to finish that, " she told presenter Simon Mayo. 

Ms Rowling was on the show to promote her new book, Career of Evil – a series about private investigator Cormoran Strike – which she is writing under her alter ego. She also said in the interview that writing under a pseudonym is "genuinely liberating."

"The deal was even if I am found out, Robert doesn't do publicity. I just like Robert's writing career to be less about the hype because I'd done so much of that with Potter," J.K. explained. 

"I'm the kind of writer who really does want to be alone writing in a room most of the time. With Robert, it feels like it's mostly about the writing, even though people know it's me."

She added that she will definitely continue to write books under her birth name, once she finds some time off from writing a new screenplay for her Harry Potter prequel, Fantastic Beasts and Where to Find Them.