Director Steven Soderberg shot Unsane mostly with a Steadicam iPhone for a budget of about $1.2 million (which is what it cost to make his classic indie sex, lies and videotape) – and the result is one of his trippiest psychological thrillers to date.

The story centers on Sawyer Valentini (Claire Foy), a woman who had to move and change her life after being stalked. Even though she’s settled into a new city and a new job, she still thinks she keeps seeing her stalker, David Strine (Joshua Leonard) – and it’s really affecting her well being.

She decides she needs to seek out therapeutic help and goes to what she thinks is an out-patient treatment center. It turns out to be a mental institution and Sawyer suddenly finds herself being involuntarily admitted for a seven-day evaluation. Much to Sawyer’s chagrin, David also shows up there as a hospital worker – and no one believes her when she tells them he’s not who he says he is. Things really start to haywire for Sawyer, but is David really there tormenting her, or is it a product of her delusion?

ScreenPicks’ Kit Bowen had an exclusive chat with Joshua Leonard about playing his creepy role and the stalker mentality. Plus, how Soderbergh might be working out some issues on his own.

Let me ask you something about Steven Soderbergh because I think he might have a little bit of a fear of being locked away without his permission.

Leonard: [Laughs] It was so fascinating to me seeing the movie for the first time. Even being in the room doing the scenes, you never really know what it’s going to look like, especially when it comes to somebody like Steven, who’s obviously got a macro vision that goes well beyond the normal human powers. Watching the film, it really made me feel so uncomfortable. I think the film, and I don’t know how much of that is the technology, and how much is just the kind of oeuvre of everything that he’s brought together to make you feel that way. It affected me on a very visceral level, and I’m in the film.

How did you tap into this guy?

Leonard: Look, I am an obsessive person sometimes. I think most of the people I know and love can be obsessive people. I also have the great fortune of having done enough years of therapy that I try not to foist my obsession onto other people in ways that makes them uncomfortable. I don’t think David Strine is necessarily a guy who ever availed himself of that.

The way I looked at David was, I just tried to tap back into teenage hormones and lust and obsession and that way that you are kind of entirely, you have these pheromone blinders on where you can’t see anything, and that love and that obsession means everything. It seems totally logical at the time.

I just removed any pre-frontal cortex development from my own brain, and I was like, look, this is a guy in a very sensitive situation who meets this woman because she’s the caretaker for his dying father. If we’re going to psychologically assess him, there’s some transference going on. She kind of becomes this angel. He falls in love with her. He assumes because his love is so pure and so big, and so true, that she will fall in love with him too, and it might just take the right delivery system or context in order for her to realize how pure and deep and true their love is.

David’s job is to show Sawyer the gift of their love. The difference between David Strine and a 13-year-old boy, being this kind of Lenny in Of Mice and Men quality, of him being a big grown man who’s going to fuck some shit up in the process, and accidentally flog and hurt some people on his way to his greater mission in life.

Did you do any sort of stalker-y research?

Leonard: I don’t know if it’s a direct story that translates or if it’s one of those had-to-be-there things, but I spent a couple of days… I don’t want to make people uncomfortable in my normal life, but I gotta get into the mindset of these guys. Talking to female friends who have dealt with stalker situations, it’s fucking terrible. It’s fucking terrible if you’re somebody on the receiving end of one of these people. I at least wanted to bring as much of that as possible because that’s who I was playing in the film. So I spent two full days cutting out pictures of Claire and making a montage of me and Claire together in our dream life, just to put myself in the headspace.

I sent some pictures to Steven. And then I destroyed the mural, and I obviously never showed Claire because she’s the loveliest and I didn’t want her to get creeped out. I’m not one of these method actor people who want her to feel uncomfortable. We can all do our jobs when the cameras start rolling.

So there was one particular night, we were about a week into filming, and we were showing each other pictures of our children on our phones. She was scrolling through and showing me pictures of her daughter, and I was doing the same. I literally accidentally swiped across one of the pictures of the collage that I had made of her and me.

She grabbed the phone, and I felt so dirty and so embarrassed. To her credit, she didn’t stop laughing for a solid five minutes. She’s an all-time great.

I’ve been obsessed with The Crown. I literally just finished binge watching it. How was it working with Claire? She was amazing in this.

Leonard: I feel like I’ve done enough weird things in my career that the five people who know me, it’s anybody’s guess to what I’m going to do next. But I think for Steven and Claire, there was a lot of preconception demolition that was going on in the process of making this film, where both of them were doing such…You know, self-deprecation aside, I had never done anything like this part before. I think we were all playing on the outskirts of things that we had tried in the past. It’s part of what’s fun about making a movie with Steven Soderbergh on an iPhone is playing a part that you’ve never played before. It’s a big experiment for everybody, but at the end of the day, if it doesn’t work, he’s going to take the heat for it.

I feel like this is kind of a companion piece to another one of my favorites of Soderbergh’s films, Side Effects.

Leonard: And Contagion!

Oh yes, Contagion, of course! But Side Effects really got under my skin, like this one did. Just under my skin!

Leonard: [Soderbergh] is also probably not the biggest fan of the pharmaceutical industry.

No indeed. Good for him, too. It can be a slippery slope.

Leonard: As I was trying to run through modern day boogie men, I kept coming back to Martin Shkreli [the guy convicted of drug price gauging]. When you go to play a character like this, as every actor will tell you, you never play somebody as a bad guy. You never play them as nefarious and mustache-twirling, and then you think of a guy like that, and he might actually be one of them. He might actually be twiddling his non-existent mustache when the camera’s not on him.

That was the thing I was going to say about stalkers in general. I’ve thankfully not had that situation. I’ve had some weird friends who’ve had a little more of a crush on me than I’d like, but I’ve never had someone follow me around. There is something sort of, as opposed to a psychopath or a serial killer or whatever, there is something a little sad about someone who chooses to stalk someone. They have a sad story, I think.

Leonard: I totally agree. It’s still that thing. You are breaking the rules of a social construct and should be prosecuted as such. But yeah, in terms of intention? I watched Misery and King of Comedy and Play Misty for Me and all the great stalker movies in prep for this, but I also watched I Think We’re Alone Now. Tiffany. The Tiffany Stalkers. Oh my god. That movie is a documentary. It’s so fucking heartbreaking.

It’s these two guys and neither of them are bad guys, they’re just really…and you know, that’s a little about what I was talking about. When you kind of don’t have the emotional maturity to have adult relationships. If that was a 17-year-old kid or even a 13-year-old kid, it wouldn’t be as dangerous as it is when you don’t grow past that and you become an adult person and you still are pursuing people with that level of obsession.

Okay, so finally, what are your thoughts about the ending and the mind-bending of it all?

Leonard: My thoughts are that the entire movie is playing with the nature of perception and how fear affects our perception.

Soderbergh’s twisty Unsane is a must-see! It opens this weekend.