In Neill Blomkamp's new film Elysium, Matt Damon wears an insane-looking exoskeleton apparatus. And we talked to Damon, one on one, about how having steel bolts in his head changes his fighting style.

Was the exoskeleton as massively uncomfortable as it looks?

Matt Damon: No actually, when I first saw the pictures of it, Neill had created this graphic novel on his computer and invented this whole exoskeleton thing, I looked at it and went "this is going to be a nightmare." I didn't say anything, but I've done 50 movies at this point. I took one look at that thing and thought it would be really rough. But they made it really comfortable. I mean I think as comfortable as they could. The only things was I was in the chair every day for about two and a half hours getting ready because they had so much stuff to put on. And so much detail work around the thing in my head and all the scars and blood. So that was it just required a little patience. But the suit itself, was kind of awesome.

Speaking of the thing on your head, how did they keep that on, glue?

Yeah, yeah so they would shave my head all the way down with a straight razor. And then just glue the thing on. And then they would have to do all the detail work around it. To make it look as if it had been surgically implanted. So that took a while — but it was cool, the prosthetics and the make up were really high quality work.

What's the difference between fighting with a physical apparatus on versus fighting in the Bourne movies?

Well actually that's a good question, because we realized really quickly that it was potentially dangerous. You had this thing that jutted out from you, and was sharp. So Sharlto and I, when we were fighting if you're going to if you're going to throw a left hook at somebody, suddenly you have to pull the punch farther away because you run the risk of slicing the person. So we all were very careful — some of the over-the-shoulder shots we'd swap out the person getting hit with a stuntman. Just because they always move better. A stuntman and an actor is always better than two actors. Two stuntmen fighting is the best. That's going to look the best. But if you have to put an actor in, it's better to do it with a stuntman.

One thing I noticed in the film is that your character interacts with the droids and the robots like they have a personality. He jokes with them, he tries to reason with them. Why was this a conscious choice for Max?

We wanted those interactions to feel matter-of-fact. To feel like real-world interactions. To just sell the idea that the world we were creating is totally real. It's something that Neill does really well. He did it really well in District 9, with the way Sharlto interacts with the aliens. The more personality he's giving them by engaging with them, the more you believe that they're there and real. And they're talking back to him. So obviously, those droids were guys in blue suits while we were making it. It's all about just trying to sell the illusion of this world.

I know in District 9 some of those scenes were impromptu. Is that something that you ran through a lot. Are there a lot of takes at the probation office that we didn't get to see?

Yeah Neill is always interested in improv-ing, and he shoots in a way that allows for that. And then in the edit, he can kind of dial up or dial down the humor. And then you have someone like Sharlto, who is just incapable to doing the same thing twice in a row. Which is what makes him so fun to watch as an actor. He's constantly throwing stuff out there and constantly giving Neill options. I thought his performance in District 9 was one of the best performances by a male lead in quite some time.