The latest installment in the ever-expanding Wizarding World of Harry Potter -- in which Turner stars as Theseus Scamander, the Auror brother of Eddie Redmayne's magizoologist, Newt -- is only one of two films the actor, 28, has opening this Friday. Elsewhere, in the gritty indie film, Mobile Homes, Turner and Imogen Poots play a couple living on the fringes of society with her 8-year-old son, dining and dashing to eat and betting on cockfights to make some money.

ET: You have two movies coming out on the same day. What does that feel like?

Callum Turner: It feels amazing. I'm super proud of both of them for completely different reasons. Vlad [de Fontenay], the director of Mobile Homes, is a very, very good friend of mine now, and I'm just really happy that the movie is reaching audiences there on the big screen.

In terms of getting both parts, I'm interested in how they were similar and different. Were they both through auditions? Do you remember the day you got each of the roles?

You know what? They couldn't have been more opposite. Fantastic Beasts was, like, a normal process. It was through [casting director] Fiona Weir and then a meeting with [director] David Yates and he met me and we talked. I think we only ran the scene once to see if he liked me. Then I screen-tested with Eddie.

Mobile Homes, Imi [Poots] had been talking to me about this project, but they had another guy who was attached. They weren't sure whether or not he was going to do it and, anyway, it turned out that he was going to do it. So, I booked a flight with my friends to go to Brazil, to go to Rio on holiday, and I hadn't heard anything. I landed and I get loads of emails from Imi and my agents saying, It's come through. It's back, you have to go to Canada in February, which will be in five days' time. So, I was switching the Copacabana for the white plains of Ontario, which was quite a shock for the system.

It was actually easier getting cast in Fantastic Beasts.

So much easier. So professional. Mobile Homes, what a wreck, when it comes to the casting process. No, actually, I spoke to Vlad and I was super interested. I'd seen his short film, which is amazing, and I really liked him. I love Imi, too, so any chance that I get to work with Imi I jump at. It was kind of a no-brainer. Luckily, the friend that I was with is in the industry, too, so he was just like, "F**king actors, man." I had to leave him in Brazil.

How was your preparation different for each of these characters? What did each require in terms of research or getting in that character's mindset?

Mobile Homes was a shock to the system in a lot of ways. I think I read the script twice before I was able to get on the plane, and I frantically read it as much as possible whilst I wasn't shooting. I work with an acting coach and it's always different. This one, Mobiles Homes, was so quick. I had to understand it and we found "Born to Run," the Springsteen song, kind of epitomized the situation and the character, Evan. I just ran with that, the rhythm of the song, the feeling of it. If I was to summarize the film, his journey, it would be: Man has dream that his girlfriend doesn't believe in anymore and he doesn't know why. That's his story, and then everything else is filtered through that idea.

What was it like for Fantastic Beasts? Obviously, they're very different characters.

It was the complete opposite. Because I had more time, too, everything was different. I kind of slowly went mad on Mobile Homes. We were isolated, the weather was severe and you could barely go outside. So, I barely went outside unless it was to film for six weeks, which is a strange reality to live in. Fantastic Beasts was the opposite. I had a lot of time. I had like two, three, maybe even four months to prepare. I just found the hook again. There was a moment in the film that didn't make it, and I recognized that as the essence of Theseus.

I didn't grow up with a younger brother -- I have a half-brother but we didn't grow up with each other -- and my research was to understand what that's like, and to get into why Newt doesn't like him and why they don't connect. The communication has gone bad. Theseus is very head-in-the-sand in a sense. He's blind to what Newt needs, and, objectively, there's a selfishness to that and an arrogance to that and a brute force-ness to that. But subjectively, it's about protection and it's about love and it's about caring. Theseus is a carer. He's described as a hugger, and I think he's trying to hug the whole world. Newt, in particular. When you aren't able to give what someone needs, to facilitate what they need, you then either push them away -- which he does -- or suffocate. I think the friction between them is Theseus doesn't understand what Newt wants, and he is overbearing. It's almost like he's got him in a big, old bear hug and Newt doesn't want that at all.

How did you like having the blond hair for Mobile Homes?

I really enjoyed that! [Laughs.] I was too quick to change it, actually. I should have lived with it a little longer. I've had blue hair, green hair and now blond hair. And also a slight ginger hair with Theseus, too.

Working with Frank [Oulton] on this, you play this young actor's adoptive father, played somewhat as an older brother, but alternatively, you have some very tough, sometimes aggressive scenes with him. What was it like between those takes with Frank?

I recognize how important it was to put Frank at ease for many different reasons. Frank and I hung out every single day with his mom, who is amazing and allowed that process. To a point where there's a scene in the film, in which I really shout at Imi and we really go at it, and Frank couldn't differentiate between us mucking around and us acting and him needing to act when the camera is on him. So, I text Vlad -- not mid-scene but in between the takes -- and I said, "Me and you have an argument." And Vlad and I went at each other. Vlad would say, "You're ruining the film. I can't believe you're doing this. I knew you would do this," and I was like, "You're such a sh*t director. I can't f**king work like this. This is ridiculous. Look at this f**king set-up, you old c*nt." And Frank's face was gold, and exactly what we wanted. Actually, the makeup girls were all freaking out and they showed the texts after. It was like a live feed of what we were saying because no one else knew what we were about to do. [Laughs.] So, it was fun. You find different challenges in working with kids and also animals. But most of all, we had a laugh while we were doing it.

They famously say don't work with kids or animals. But, in this, I was thinking, That kid is very good at working with the chickens!

Because he grew up on a farm, so he knows! He's legit with the animals.

How did you like the chickens?

Yeah, I got involved. I got involved. I just had to. There wasn't any sort of beating around the bush. I quite enjoyed it. You know, what I really like about Evan -- and what Vlad allowed me to play -- is a ferociousness and aggressiveness. He's wild, man. He's f**king wild. I just really enjoyed really going for it.

How much time did you have between Mobile Homes and Fantastic Beasts?

About a year. I did a film called Only Living Boy in between.

With Kate Beckinsale.

Yes!

Which was, I think, bigger than Mobile Homes, but certainly not as big as Fantastic Beasts.

There's definitely an evolution there, if you look at it like that, yeah.

I imagine that helps. If you went from Mobile Homes directly to Fantastic Beasts, that seems like a whiplash. What was the hardest thing to adjust to on such a massive franchise film set like that?

If I'm going to be honest, the only thing you really have to check is how big it is. Once you're over that -- you know, The Wizarding World, the fandom, the fans are amazing, J.K. Rowling [and] all these people being really famous --  once you're past that and you're doing the job, the work, it's always the same.

There's a great story of Al Pacino and Christopher Nolan, when he cast Al Pacino [in Insomnia]. On the first day, he's like, "It's a bigger set. It's a longer drive to set. Bigger calls, better craft," and Al Pacino just looked at me and was like, "Don't worry, you're home." And you do have that sense, especially the ways David Yates creates an intimate environment. It feels like we're shooting a small independent movie because it's grounded. These films are grounded in human performances, and that's what's exciting as an actor. It's a classy franchise. Or it's supposed to be.

The critics' reviews of Fantastic Beasts have come out, but now fans are getting the chance to see the movie. What has been the reception you've seen so far?

Oh man, we make these films for the fans. We make these films for the people that love this world. Myself included. Even before the film was released, people had accepted me as part of the family, and I'm so touched by that. I hope they feel the same come Monday. [Laughs.] Yeah, it's mostly I love it! When the music starts going, the Harry Potter music, it gives me tingles. It's an honor to be a part of it.

How much were you told about Theseus' arc into the next movie and over all of the movies before you signed on?

None. All of us are in the same position, apart from Jude [Law], apparently, who knows all.