JK Rowling has finished writing the script for her Harry Potter spin-off movie.

JK Rowling
(Debra Hurford Brown/Pottermore/PA Wire)

The author has been hard at work on Fantastic Beasts And Where To Find Them, which was inspired by her 2001 fictitious wizard textbook of the same name and will be about its fictional author, a “magizoologist” named Newt Scamander.

Producer David Heyman told the Daily Telegraph: “Jo has written a wonderful script.

“It’s early stages.”

The cast of Harry Potter - Daniel Radcliffe, Emma Watson and Rupert Grint - and JK Rowling
The cast of Harry Potter – Daniel Radcliffe, Emma Watson and Rupert Grint – and JK Rowling (Ian West/PA)

He revealed the movie – which is set years before the adventures of Harry and his friends Hermione Granger and Ron Weasley, played by Daniel Radcliffe, Emma Watson and Rupert Grint in the hugely successful franchise – would start shooting next year.

“I’m just really excited about it,” added Heyman, whose company produced all the films about the boy wizard.

David Yates will direct the film, which is the first instalment in a planned trilogy. He was also at the helm of the last four Potter movies.

Fantastic Beasts And Where To Find Them will be released in US cinemas on November 18, 2016.