J.K. Rowling is set to adapt her Harry Potter spin-off book Fantastic Beasts and Where to Find Them as a series of three films.

The movies will all be based on the novel, which is actually a Hogwarts textbook, originally mentioned in Harry Potter and the Philosopher's Stone, and it will follow magizoologist (a person who studies magical creatures) Newt Scamander and start in New York approximately seven decades before Harry Potter’s own adventures.

In the book Scamander says that he collected most of the information through observations made over years of travel and across five continents, and includes 75 magical species found around the world.

The news was revealed in a profile of the Warner Bros studio’s CEO, Kevin Tsujihara, in The New York Times. who Rowling credits with being responsible for convincing her to create the films.

Rowling said: “When I say he made Fantastic Beasts happen, it isn’t P.R.-speak but the literal truth.

“We had one dinner, a follow-up telephone call, and then I got out the rough draft that I’d thought was going to be an interesting bit of memorabilia for my kids and started rewriting!”

Famously, Rowling, real name Joanne, came up with the idea for the Harry Potter books on her way from Manchester to London, when she was on a delayed train.

The author's magical novels have become the best-selling book series in history and the films, all based on the books, became the highest-grossing movie series in history.

She is also the UK's best-selling author since records began, with sales in excess of £238m.

(Image: Rex Features)

Three new Harry Potter movies in the works