The Harry Potter movie franchise is one of the highest-grossing ever and the fans span the globe in their legions.
So of course it makes sense to mainline back into that fan base and that's exactly what JK Rowling has done with the first of five new movies.
Diehard fans will know Fantastic Beasts and Where to Find Them was the textbook their hero Harry read at Hogwarts.
Rowling has taken the shy, clumsy author of the book - Newt Scamander - and turned him into her new magical hero.
Her first great move was to cast Oscar-winning Eddie Redmayne as Newt and speaking to the cast, it's clear they are in awe of Rowling and her astonishing imagination.
"Lots of the crew had worked on the Potter films, so they are such a lovely group of people and a cozy group of people, that they made us feel like we were making a small indie film. They tricked us!" says Redmayne.
The spin-off is set before Harry is born in New York City, giving Rowling an entirely new era, a new setting and new characters to play with.
Irish actor Colin Farrell is also new to the Potter universe, but knows the fans are nothing to be sneezed at.
"She put all that energy and focus and all that respect for imagination and the human race, ideas of how we interact with each other and ourselves even, on paper. It's amazing what JK Rowling has put out into the world; it's really nothing short of a miracle," he says.
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