`Harry Potter` author J.K. Rowling is worried she will die before she finishes writing her new children's books.

The 50-year-old is busy working on new material and revealed she has "so many ideas" to put down on paper - but she fears she won't have the time to realise her ambitions, reports femalefirst.co.uk.

`I sometimes worry I'll die before I've written them all out. That's my midlife crisis - that I will leave this earth without having written them all,` Rowling said on a radio show.

The award-winning writer also announced plans to return to the professional name of J.K. Rowling, having written some of her last few works, including the crime novel `The Cuckoo's Calling`, under the pseudonym of Robert Galbraith.

She said: I have plans to write novels - in the plural - as J.K. Rowling again but I'm not going to give you an absolute date because things are busy enough.

"I have an idea for a children's book, which I really love - I've been writing part of a children's book so I'm going to finish that - and I have ideas for other adult books."