Warner Brothers has released Fantastic Beasts: The Crimes of Grindelwald’s full cast list, and it reveals another big face from the Harry Potter series appearing in the spinoff series.

Until now this has been a huge secret. Obvious spoiler warning!

Within press materials released by WB on Thursday, a certain Harry Potter character and a new actor playing them was revealed. And no, it’s not Nagini. Are you ready?

Are you sure?

Accio, surprise…

Minerva McGonagall.

Yep, the Hogwarts Transfiguration teacher will appear in The Crimes of Grindelwald, according to press materials released by WB and reviewed by Hypable. She appears in a list that’s sorted by order of appearance, and for what it’s worth, she appears roughly 3/4ths of the way down the list.

Immediately after McGonagall in the list is Young Grindelwald and Young Dumbledore (The ones played by Jamie Campbell-Bower and Toby Regbo. The two actors also appeared as Young G and D in the Harry Potter movies).

She’ll be played by Fiona Glascott, a 35 year old actress born in Ireland. She’s a relatively unknown actress, having had roles in Showtime’s Episodes, the 2015 film Brooklyn, and the 2002 Resident Evil.

But here’s the thing: Unless McGonagall makes some sort of appearance in a flash-forward, it looks like J.K. Rowling has drastically changed her age. According to canon, McGonagall started attending Hogwarts in 1954, meaning that she was born around 1935. The Crimes of Grindelwald is set in the 1920s. As the Harry Potter Wikia explains:

McGonagall’s year of birth can be calculated as 1935 from her Pottermore biography and Harry Potter and the Order of the Phoenix, Chapter 15 (The Hogwarts High Inquisitor), which reveals she began Hogwarts in December 1956 after working for the Ministry for two years immediately after graduation. This places her graduation in 1954, her first year in 1947, and her birth in 1935 (because of her October birthday, she was almost 12 when starting at Hogwarts

This math is backed up by the HP Lexicon, who explains it in more detail.

We don’t know what McGonagall is up to in The Crimes of Grindelwald. It could be a brief cameo at Hogwarts or it could be something more significant. Since the actress is in her mid-30’s, she’s obviously not playing a student.

Update: A source tells me that McGonagall is indeed a Hogwarts teacher in The Crimes of Grindelwald. Her first name is not used in the film, but the cast list released by WB specifically lists “Minerva McGonagall.” She doesn’t have an important role in the film and appears twice. One scene is a flashback to Newt’s days as a Hogwarts student, and the other scene shows her at 1920s Hogwarts. She’s a teacher in both scenes. My source says that she doesn’t serve a purpose other than being a cameo for fans.

A mid-30’s McGonagall in the 1920s is a pretty serious change from canon. The question is, do we care that Rowling is changing things like this in order to delight moviegoers?

We couldn’t find any other surprises in the cast list, but we did notice that Credence’s Aunt has been cast, as well as a Young Yusuf and two young Leta’s (one who’s 3-6 years old, the other who is 13-16 years old).

Let us know what you think in the comments below. Crimes of Grindelwald arrives later this month.