by Kyle Buchanan

In Hollywood, Justin Theroux puts most other multi-hyphenates to shame. The 38-year-old actor is already well-known for roles in film (Mulholland DriveCharlie’s Angels: Full Throttle) and TV (Six Feet Under), and he even directed the Sundance entry Dedication, but after co-writing the Ben Stiller comedy Tropic Thunder, he’s suddenly become the town’s most in-demand screenwriter. Iron Man 2 is his latest credit, though Theroux’s got many more scripts on his plate, including Space InvaderChief Ron, and Zoolander 2, the latter of which he’ll direct. (If you’d rather see him in front of a camera, never fear: he’ll play the villain in next year’s James Franco/Danny McBride stoner comedy Your Highness).

Movieline already teased a little bit of our interview with Theroux; now, here’s the rest, where he describes his unlikely career shift, the unorthodox Iron Man 2 writing process, and what he’s got planned for the Zoolander franchise.

From my perspective, your opportunities as a writer just took off after Tropic Thunder. Had you been intending for it to become such a big part of your career?

I never thought it would, but I wanted it to become a much bigger part of my career as I was working on Tropic Thunder, just because I really like the way your days work when you’re a writer and on-set. I haven’t ever not been an on-set writer on the two [produced] movies I’ve worked on, not really. There’s also a certain amount of writing you do when you’re an actor — when you’re working with friends, at least — and I’ve done a fair amount of my own little punch-ups with other writers on other things that I’ve worked on.

What was it about being an on-set writer that made you think, “I’d actually kind of like this”?

It wasn’t so much being an on-set writer as it was the fact that for better or worse, in the industry in general, actors get to have a say in what they do. Especially if you’re working with people who are funny, they might ask for your input as well, and so you get to enact ideas and jokes that you have to want to have in there. I’ve been working on stuff where I’m allowed to put my two cents in there during the development or the rehearsal process. Especially with comedy, it sort of encourages improvisations that aren’t on the page, that can only happen on set.

I know that you did a lot of on-the-fly writing with both Tropic Thunder and Iron Man, but from what I understand about Jon Favreau’s method, you actually did a lot of on-the-fly plotting with Iron Man.

It’s different with Iron Man because when you’re dealing with special effects, it’s a much bigger rolling stone. Not that Tropic didn’t have that, but there are certain things that are changeable and certain things that are unchangeable, effects-wise. As you shoot them, those things go off the table, obviously, and you can change less and less. But yeah, we were moving heavy pieces of furniture well into shooting.

So how would that play out? You’d notice a moment or a plot or some chemistry that you liked, and write more toward it?

It was either that things were going well or Robert would discover something in his character during the day that he’d gravitate to, so we’d write more towards that. Maybe there were scenes that we realized we could deepen. It was very mercurial, changing things, and it was sort of a wonderful way of working. It’s not unlike when you do a play or something, and you have around five weeks of rehearsal where you can explore and touch all the walls of the room, so to speak. There are times that you wish you had that on film, because a lot of those times, the first time the actors are even saying these lines to each other is the day they’re shooting it. So, if nothing else, a lot of the time we discovered stuff on [Iron Man 2] was that morning, where we’d go, “Oh, [the actors] are doing that, so let’s write more toward that.” A lot of times, we were just writing stuff on the lunch break for that afternoon’s work.

What’s a scene that changed a lot through that method?

The Pepper Potts CEO scene is a great example of that. We knew what the scene had to do, we knew that she was going to come downstairs angry and that he was giving his art collection away to the Boy Scouts of America, and at the end of the scene, the objective was to make her the CEO. And then [Gwyneth Paltrow came in] with a cold, Robert started riffing on that, saying, “Don’t make me sick” — it’s like taking what the day is giving you and writing towards it. It gave us real, spontaneous moments where he’s remarking, like, “Don’t breathe on me,” and that just happened to play with the [blood poisoning subplot] with his character, and [Gwyneth’s] voice didn’t sound quite right, so we had to justify it. It was just like, rather than come in and pretend that she doesn’t have a cold and that’s not happening, why not write to it and get these great little nuggets of character that fall out of that?

It sounds almost like black box improv, where each actor has an objective and they just go.

That may be oversimplifying it. Robert is an improv baller, so he’ll throw stuff in anyway and he’s great at it, but we would try to recognize what those things were and write towards them on the day. A lot of times, they would do the scenes exactly as written.

At the Iron Man 2 press conference, Favreau seemed almost apologetic for causing you physical pain on set. What happened?

[Laughs] I slipped a disc in my back. I was sitting in a bad chair on set, hunched over a computer writing for so long, and I tweaked my neck towards the end of shooting. I had to have all sorts of cortisone injections and be wheeled in on a stretcher, practically. I had major back and neck pain.

This film also had a luxury that many tentpoles don’t — it had almost a full year in post-production, and you even got to go back for a few weeks of reshoots. How did that help?

Jon likes to say that the last part of the writing process is the editing. We had so much material that we’d shot, so much usable and unusable footage, and I think once we got in the editing room, we realized, “Oh, we can sweeten this, we can draw this out here.” I don’t like to really dissect the post schedule because a lot of those decisions were Jon’s — I wasn’t really in the editing room — but I trust that all those decisions were well thought out.

What’s it like to be the subject of all this scrutiny as a writer, instead of as an actor?

I try to take everything with a grain of salt. I don’t really read reviews; I’m not hearing any praise, and I’m not hearing anything negative, really. I just try to do my job and leave it at that. It doesn’t help you, you know what I mean? You learn your mistakes during the endeavor — you don’t learn them afterward by someone wagging a finger at you or patting you on the back. There will always be things that I love or things I wish I could have changed.

So what did you love about Iron Man 2?

I really love that we addressed that character in real-world terms, or as real as possible for a superhero movie. I like that we met the last part of the first movie head on, him saying, “I am Iron Man,” and addressed what happened when a guy comes out as a superhero and has to live on those terms in the real world.

With Iron Man 2Tropic Thunder, the Zoolander sequel, and some of your other projects in the works, you’ve written for directors who also act. How might they approach material differently than a normal director?

I don’t know, because now that I think of it, I haven’t written for a director who’s not an actor! They can cut to the chase a lot quicker, and they can essentially be acting the movie in their heads as they’re reading your pages. I think actor-directors just have a really good bullshit meter. They know what won’t work, as hopefully do I. They can spot excess fat in a script quicker than most people.

So you’re saying that the Zoolander sequel is still on, as far as you know. Is there a shoot date?

No, there’s not a shoot date yet, because there’s no script yet. I’ve gotta get the script in first, and once that happens, we’ll start pre-production and pick a date to start shooting.

Is it easier to write something larky like Zoolander 2, as opposed to an Iron Man sequel?

The obligations are different. For Iron Man 2, there are certain things you have to address, there’s a template for where that movie has to go, there’s action scenes, et cetera. The characters are pre-set — as are the ones in Zoolander, but we maybe get to have a little more fun playing with it in Zoolander. We can sort of poke fun at the fact that it is a sequel, and you don’t have to be as reverential to the characters, necessarily.

Did you really go to Fashion Week in Paris as research?

I really went to Fashion Week in Paris!

And what did you take from that experience?

It’s just really fun. The whole point of fashion, really — or at least, the point during the shows at Fashion Week — is to be outrageous and over the top, and boy, do they do it! It’s like a prettier Hollywood. [Laughs] It’s completely absurd.

You strike me as a pretty fashionable guy, though. Had you been to many fashion shows before this?

I’ve been to fashion shows in New York before, but just as a bystander. This time, I felt like I had a little more at stake. I had a really good time. I laughed more this time, watching it through that prism of [Zoolander].

Are you guys still proceeding with the assumption that you’ll have Owen Wilson and Jonah Hill on board?

Yeah, we hope so. We hope so.

Jon Favreau upped his own screen time in Iron Man 2. Will you take a cue from him and give yourself more to do as the evil DJ in Zoolander 2?

[Laughs] I’m gonna make it all about the DJ! You know, if there’s a place for him in the story, I’ll put him there for sure, but there might not be. We don’t know. We’re trying to figure it out.

Last question: Laura Harring recently said that she thought David Lynch was formulating a sequel to Mulholland Drive. Have you heard anything about it?

I haven’t heard that at all. I would be shocked if that happened. I would not expect it.