For many years, 24-year-old Ezra Miller was thought to be an actor who was going to explode at any time, given his amazing performances in We Need to Talk About Kevin and The Perks of Being a Wall Flower. That time came in 2014 when Miller was cast as The Flash in Warner Bros. and DC Entertainment’s attempt to create a big screen shared universe based on DC Comics’ characters. Miller’s Flash has appeared briefly in both Batman v Superman and Suicide Squad, but he’ll play a much bigger role in next year’s Justice League.

That trend continues with this week’s Fantastic Beasts and Where to Find Them, J.K. Rowling’s latest foray into the world of Harry Potter, in which Miller was cast as Credence, a young man in 1926 New York who is part of a cult-like group trying to rid the country of “witches” along with his cruel foster mother Mary Lou Barebone (Samantha Morton).

Of course, any such organization is going to come into conflict with America’s own wizards including a visiting Newt Scamander (Eddie Redmayne) whose briefcase full of creatures is accidentally loosed in the city, causing a conflict between the wizards and the “No-Majs” (as Muggles are called in the States).

Collider spoke with Miller at the film’s New York junket and we immediately realized what a huge Potter super-fan he really was.

Collider: I got the impression when we last spoke about four years ago that you were shying away from doing big studio movies or franchises, and now you’re doing two of them that might keep you busy for ten years or more. What changed your mind?

EZRA MILLER: I was just attracted to the stories in a way that I couldn’t deny. My love of the DC Universe when it came time to make that decision was very over-powering, and certainly, the same can be said about when I got the call regarding Fantastic Beasts. 

What did they tell you about Credence? What did you know about the character? Were there a lot of details? 

MILLER: They told me only one thing, which was that he had a trying relationship with his foster mother, and based on that, I did an improvisation, which was a great exercise. One of the more interesting initial auditions that I’ve ever been assigned, and then I had a meeting with David Yates and David Heyman in New York—not far from here actually. Yeah, and then I went through the biting and the chewing for a couple weeks while they made their decision.

At first, I thought this was a very different character but you had characters with mother issues, quite a few times before, so it’s not that far, but Credence doesn’t fight back in some ways.

MILLER: Sure, I guess in terms of the journey into archetype as an actor, you would hope that there would be a few explorations of complex relationships with mothers. (laughs) It certainly would please the psycho-analytical part of my acting ambitions.

You also tend to play the guy who is joking around and you do a lot of improv and have experience with that, but Credence is sullen, he barely talks… 

MILLER: Yeah, this was the first film I’ve done in a long time probably where I didn’t change a word. Usually, you say, “It’s not Shakespeare or anything” but in this case? It’s J.K. Rowling! (laughs) There’s a reverence towards the words.

And it’s not Steve Kloves adapting her, it’s actually her.

MILLER: Yeah, it’s HER words, so yeah, there was a strong incentive to be very reverence towards the material and to work as hard as I could to honor her intent.

I think you’re about 24 years old, so when was the first time you got into that world or even saw a Harry Potter movie? Must have been either when it very started or while it was already going. 

MILLER: My introduction, actually, was close to the beginning when I was about seven reading the first book, or more specifically, to be more precise, my father reading the book to me, which was a wonderful part of my childhood, being read to. I think some of my first favorite performances were those of my parents reading children’s books, and then just got obsessed with the series—read all the books. I really was just a Harry Potter kid. I listened to the audio books almost every day. It was my security blanket, it was my scripture to listen to the Jim Dale performances of Harry Potter, so the material is really embedded in my being in a way that seems like it’s finally paying off. (chuckles)

At what point did they show you the haircut that Credence would have for this role? 

MILLER: So when I first met with Faye Hammond, our incredible hair and make-up department head, she had all of these wonderful pictures from the era, from the 1920s. We looked through a lot of them. There was this one image she had chosen of a boy with a haircut very similar to Credence’s, and we just agreed that that was the perfect way to express the reality of this character. I mean, I had REALLY long hair when I went in, but we agreed. I was sad to agree, but I did agree, that Mary Lou probably put some sort of shallow bowl—the gruel bowl. She put the gruel bowl on his head, and with some blunt scissors, chopped around the edge, and that seemed just perfect for the character, so we went with it.

I get the feeling J.K. Rowling went in and wrote the movie but I’m not sure if she had a long game at that point, but did you get the impression that Credence might be back some day? 

MILLER: I don’t know, I don’t know. I mean, I’ll tell you, it’s a mystery, it’s a mystery to us all. She’s the carrier of the knowledge.

I’m a huge Flash fan so it’s nice to have teases in the other movies so far, and they’ve been very different as far as the character. Has that helped you build the character going into Justice League or your own movie? 

Miller: Yeah, I mean, I’ve been investigating and composing the character since the moment I started to consider doing the screen test. Fortunately, a lot of that research is extremely fun and involves reading Flash Comics and other comics from the world of DC, The Brave and the Bold.

Oh, you went back that far? You went way back. 

MILLER: Yeah, oh, I went all the way. I’m really interested in the early history and some of my favorite stuff has been the Silver Age. Even the Golden Age and the Jay Garrick stuff, the original Flash. It’s just so fascinating, so endlessly compelling. It’s such an incredible set-up for exploration, all these fascinating concepts in physics, in mysticism, in fantasy… I mean, he can really go anywhere. He’s that figure of the DC pantheon who transcends the realms, sort of like Hermes or Mercury before him in the respective Greek and Roman mythologies that the character’s (creator) Gardner Fox, clearly very much based.

And then you have a Flash super-nerd like Geoff Johns who loves the character… 

MILLER: Yes! He’s a good guy to have around. He keeps us full of information and he keeps us from making ignorant mistakes that would upset the fans across the world because you pretty much can’t get someone with a deeper knowledge of this universe than Geoff Johns.

What’s going on with the movie now? Obviously, a couple directors have left. Is that because they can’t handle “The Ezra”? 

MILLER: Oh, God!! (laughs) No, you know, these processes are complicated, and I think it can, and I think from afar, it can appear to be--as you say--something interpersonal or dramatic. That is rarely the case. These are groups of people taking the development of projects extremely seriously, and the teams are changing all the time. There’s often a lot of flux in who the team of the production of a film is before that production starts, and in this case, you hear about it, because it’s a critical figure—the directors that have been coming on and leaving.

At least Phil Lord and Chris Miller had a good excuse, since they got a Han Solo movie. 

MILLER: Sure, yeah. For me, it’s sort of a tragic relay race, and we’ve had a couple really incredible people carry this baton, and their marks are left on that baton, and the work that they’ve given to the project will certainly be represented in whatever the final product comes to be.

Have you read a script and are you pretty happy with where the script is or are you just getting pieces and not knowing that much? 

MILLER: I’ve had glimpses of various points in the development of it. And I’m extremely excited.

Fantastic Beasts and Where to Find Them opens nationwide on Friday, November 18 with previews on Thursday night. Click here to read Matt's review.