J.K. Rowling reveals how long it took to write first 'Harry Potter' book

J.K. Rowling is recalling the moment she realized her brainchild Harry Potter had become a worldwide phenomenon.

Rowling’s series of Harry Potter books center on Harry’s years at Hogwarts School of Witchcraft and Wizardry and his fight against Lord Voldemort.

The series sold more than 500 million copies across the world, whereas the movie franchise is worth more than $10billion.

Rowling published the first book, titled Harry Potter and the Philosopher’s Stone (called Sorcerer’s Stone in the US) in 1997.

She told The Sunday Times newspaper she realized how big it had become when she won the Smarties Book Prize in 1997. “Then I got a record advance from America, and everything went crazy,” she said.

She also revealed that it took her seven years to finish the first book as she kept doubting it:

“I kept losing hope and putting it away, but that happened less and less as I worked on it. At a certain point it, or I, caught fire, and I stopped doubting. I can remember feeling elated after writing the first Quidditch match, which flowed out of the pen and was barely revised afterwards.”