The third - and final - trailer for Fantastic Beasts: The Crimes of Grindelwald was released this week.

And, with it, Harry Potter fans got to find out the secret that J.K. Rowling has been keeping for "around 20 years". Many fans had been speculating about the identity of the character played by Claudia Kim - seen on the left side of the cast photo, right beside Ezra Miller's Credence Barebone. The new footage revealed the answer: Nagini. Yes, as in He Who Must Not Be Named's beloved snake - and one of his Horcruxes. https://www.youtube.com/watch?v=8bYBOVWLNIs&t=37s Nagini is actually a Maledictus, a woman who carries a blood curse from birth that causes them - eventually - to turn into a beast. Towards the start of the trailer, Ezra Miller's Credence whispers "Nagini,"as Claudia Kim's character can be seen turning into a snake. And it turns out that social media users were just as shocked to learn about Nagini's origins are we were. https://twitter.com/joshwilbanks_/status/1044749715055804417 https://twitter.com/Faseeha_Hajat/status/1044894883989917697 https://twitter.com/arepyong/status/1044724099186970625 https://twitter.com/xtineMAY/status/1044733093364428800 https://twitter.com/Pibu_Ra/status/1044897066206588928 https://twitter.com/kieomalin/status/1044878539974209537 And that led many fans to wonder: just how long had J.K. Rowling been keeping this a secret? https://twitter.com/jk_rowling/status/1044579634581401600 The author hinted at plenty of other twists and turns for fans when Fantastic Beasts: The Crimes of Grindelwald hits cinemas later this year. The film is due to arrive in Irish cinemas on November 16.