There's a new Fantastic Beasts trailer and it confirms a massive Harry Potter fan theory.

The final trailer for the next Fantastic Beasts movie has been released, and it’s delivered a surprising revelation.

The Crimes of Grindelwald, which picks up where Fantastic Beasts and Where To Find Them left off, is due to be released on November 15, but the trailer alone has already confirmed a massive fan theory.

For years, Harry Potter fans have questioned whether Voldemort’s horcrux pet snake Nagini has always been a snake.

And now, thanks to the new trailer, the long-running fan theory has finally been confirmed.

According to the trailer, Voldemort’s pet snake was actually previously a witch.

You can check out the new trailer for Fantastic Beasts: The Crimes of Grindelwald below.

But while fans believed this might mean Nagini was an Animangus, like Peter Pettigrew or Professor McGonagall, author J.K. Rowling has set the record straight.

“Not an Animangus. A Maledictus. Big difference,” she told a fan on Twitter.

According to Harry Potter Wiki, a Maledictus is a term used “to denote a female individual whose blood has been cursed from birth, and would eventually lead her to turn into a beast”.

J.K. Rowling also explained the difference between werewolves and Maledictuses on Twitter, sharing that Maledictuses like Nagini are always female.

They’re different conditions. Maledictuses are always women, whereas werewolves can be either sex. The Maledictus carries a blood curse from birth, which is passed down from mother to daughter. https://t.co/wYfvPeQFRW

— J.K. Rowling (@jk_rowling) September 25, 2018

Understandably, fans of the franchise were stoked to see the long-running theory confirmed.

“Nagini was a human woman all along“ really is a bold addition to JK Rowling’s list of post-series canon retcons. https://t.co/H3TsQplrwR

— Gavia Baker-Whitelaw (@Hello_Tailor) September 25, 2018

UM????????? NAGINI??????? I KNEW THERE WAS ALWAYS SOMETHING MORE UP WITH THAT SNAKE https://t.co/6nlbGq7VLM

— ????lauren (@renontheroad) September 25, 2018

I knew Nagini wasn’t an ordinary snake when Voldemort made her a horcrux. And I was right! The Slytherin ring and the locket, the Hufflepuff cup, the Ravenclaw diadem etc and a snake??? It just didn’t fit ????????‍♀️ #FantasticBeasts

— Snitch (@justinsbicep) September 25, 2018

Claudia Kim, who will play circus performer witch Nagini, spoke to Entertainment Weekly about her upcoming role.

“It will be so interesting to see another side of Nagini,” she told reporters.

“You’ve only seen her as a Horcrux. In this, she’s a wonderful and vulnerable woman who wants to live. She wants to stay a human being and I think that’s a wonderful contrast to the character.”

We don’t know about you, but we are very excited to see this side of Nagini.

Fantastic Beasts: The Crimes of Grindelwald premieres in Australian cinemas on November 15.

What do you think? Are you excited for the next instalment in the Fantastic Beasts series?

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