Story highlights J.K. Rowling will make her screenwriting debut with a wizarding movie

It'll be based on one of Harry Potter's textbooks

Studio Warner Bros. says it's the first in a film series

J.K. Rowling still has some tricks up her sleeve.

The "Harry Potter" author is returning to the world of wizards that made her famous, but it's not going to be with a new book -- and it's not going to feature The Boy Who Lived.

Instead, Rowling is going to make her screenwriting debut with a movie centered around one of Harry Potter's textbooks, "Fantastic Beasts and Where To Find Them," and the sojourns of its author, Newt Scamander.

According to Rowling, she became intrigued with the idea after a proposal from studio Warner Bros.

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The author says in a statement that the studio (which shares a parent company with CNN) approached her "with the suggestion of turning 'Fantastic Beasts and Where to Find Them' into a film," which she thought could be interesting, but wasn't excited to see handled by another writer. After inspiration struck for what she could do with the story, she says she ended up pitching her own plot.

"Having lived for so long in my fictional universe, I feel very protective of it and I already knew a lot about Newt," Rowling says. "As hard-core 'Harry Potter' fans will know, I liked him so much that I even married his grandson, Rolf, to one of my favorite characters from the 'Harry Potter' series, Luna Lovegood."

But while "Fantastic Beasts" pulls inspiration from the "Potter" universe, Rowling is very clear that this movie isn't a prequel or a sequel of that franchise, which ended with 2011's "Harry Potter and the Deathly Hallows: Part 2."

Instead, with the project being "set in the worldwide community of witches and wizards where I was so happy for 17 years," Rowling says it should be considered "an extension of the wizarding world. The laws and customs of the hidden magical society will be familiar to anyone who has read the 'Harry Potter' books or seen the films, but Newt's story will start in New York, 70 years before Harry's gets under way."

According to Warner Bros., "Fantastic Beasts" will be the first in a planned series of films. In addition to the new franchise, Warner Bros. Entertainment has also entered into an "expanded creative partnership" with Rowling, which will cover projects like video games, digital initiatives and tourist attractions.