Iain De Caestecker Talks Playing Agents Of S.H.I.E.L.D.'s Fitz - Exclusive Interview

The final season of Marvel's Agents of S.H.I.E.L.D. has been full of mysteries, but there's only one at the top of every fan's mind: Where is Fitz? Leopold Fitz, half of the fan-favorite 'ship Fitzsimmons and one of the most popular characters on the show, has been missing since S.H.I.E.L.D.'s season seven premiere. Now, with the series finale looming, people are beginning to get nervous — especially with the Chronicoms hot on Fitz's trail.

You won't find any spoilers for the S.H.I.E.L.D. finale here — our chat with Iain De Caestecker, who's played Fitz all these years, was conducted before the season debuted — but if you're jonesing for a quick Fitz fix, this should tide you over. In our exclusive interview with De Caestecker, the S.H.I.E.L.D. star discussed his favorite Fitzsimmons scene, how he got ready for his shocking turn as the Doctor in season four, and his dream MCU team-up. Watch out: that last one might surprise you.

You've been playing Fitz for seven years. What's the biggest lesson you've learned from him?

Probably just someone that does the right thing. He's got quite a strong moral compass, usually, and that's definitely something to be admired. He definitely is braver and is more courageous than I am.

You know, there are superheroes that have courage, and there's somebody like Fitz, who doesn't have the stereotypical superhero powers. And I think, really, he's in a unique place, getting caught up in those situations. I couldn't say I would do what he did.

And then, also, you can't really talk about Fitz without talking about Simmons. She had a similar thing, that courageous nature and that ability to always do what's right, to stand up for what she believes in. These are traits that I would like to say that I've learned and taken, but I feel nowhere near as smart. I mean, that's another thing. I should be better at science by now, shouldn't I? But nothing. In one ear, out the other.

How did you prep for Fitz's transformation into the big bad of season four?

Yeah. That was a real learning curve. I can talk about that in terms of a real learning curve, because I've never done something like that. I mean, if I could go back and do it again, I would. There are certain things I would change about it, I think. But I did like how that character is not, like, twiddling his mustache. He's still rooted in reality, or meant to be. He lets other people do the dirty work for him. He's not someone that suddenly muscles up and learns karate.

And so that was a bit cool, and that took a while to adjust to. I think part of the nature of the show is it does run on quite a quick schedule. Which is, I find, really useful, on one hand. But sometimes you start a new character like that, and you feel like you only pick him up a few episodes into doing it.

But yeah, I do research a bit. Watching documentaries is something that I'm quite big on for research. And I'll maybe try and find the character somewhere, or somebody that I think identifies a lot of the attributes for situations or circumstances that the character's going through, and then kind of really hone in on that, try and pick up little bits. But yeah, research for me is usually quite sporadic. And I usually pick up lots of different things. Sometimes I even watch other actors in movies.

And also, the other thing is, a lot of the work's done for you by the writers as well. That's kind of predetermined. And the costume, the make-up, and the hair. One day I was at home, and I got out of the shower, and I just parted my hair onto the side, and it was shaved a certain way and it was dyed, but I was kind of like, "Oh, this is a bit Hitler Youth." And I emailed a photo to Maurissa [Tancharoen], the showrunner. She liked the idea of it. So did Jed [Whedon]. They were like, "Do it." And so, just little things like that. Build up the character piece by piece.

Do you have a favorite Fitzsimmons moment?

Gosh, there are loads. I like the bad stuff. When Simmons is trapped, I liked how they did all that stuff for their new cool storyline, and it was kind of a big shifting point in their relationship.

I don't know. I'm being sentimental now. I never really thought about it, but looking back, I really like the season one stuff. I like the kind of the lightheartedness and everything. They look a little bit more cartoony in season one, which that's just fun, you know? The show was, rightly so, and I've gone at it in a little bit of a more serious direction tonally. But it's nice. Season one kind of had a bit more of that lighthearted feel between the two of them, and I also enjoyed that about it.

You haven't appeared in the movies, but if Fitz could team up with one character from the big screen Marvel universe, who would you choose?

I mean, I would always probably have said someone like Iron Man, or like Bruce Banner, just because of the scientist correlation.

What about you, personally?

I mean, I reckon I'd quite like to work with one of the bad dudes, like the baddie. Like... What was that guy? Thanos?

Thanos, yeah.

And just like go in, and just have a chat. As long as you know you're not going to just die straight away. Just go in and be like, "What happened? What happened to you? What's making you do this? Why are you so unhappy? Talk to me. Let it out. Maybe let's see if there's a better way to resolve this situation. And if there's not, I'll let you go. I'll let you win. And I'll make sure of devastation. But, first, let's just sit down and talk about this for a couple of hours." That's what I would do.