The man who once played a 10-year-old stuck in a middle aged man's body (Step Brothers) did some growing up with Cyrus, his latest film that stars Jonah Hill, Marisa Tomei, and himself. Created by very natural filmmaking methods such as improvisation, the film presents human beings that straddle the lines of maturity for better or for worse. An actor that hops between oaf-ish characters (like Cal Naughton in Talladega Nights: The Ballad of Ricky Bobby) to serious dramatic human beings (Magnolia), it's fair to say that Reilly knows a bit about this concept, and is well aware of the equal effort that goes into bringing either type of character to life. I sat down with the versatile actor in a roundtable interview to discuss the making behind the new film, along with the acting choices he has made in the past, and what we have to look forward from him in the future. What in particular attracts you to movies abut men who have a crisis with maturity?

I play a pretty mature character in this movie, I think. I don’t know. You know, as an actor, I wish I could say it’s me picking everything, but a lot of my life is the work just coming to me. For whatever reason, people just see me as somewhat of a child, or have in the past. Maybe that’s my optimism. But I was just drawn to this movie because Mark and Jay Duplass are really talented, and they like to improvise. They told me that they wrote this character with me in mind.

How in terms of style and preparation does it compare when playing a character similar to the one in Talladega Nights, as opposed to John in Cyrus?

I try to do the same kind of work preparing for things whether its’ a comedy or a drama. I don’t do less preparation because it’s a comedy. You try to know as much as you can about where the character is coming from, and what they do for a living. But when you do a lot of improvisation like with this movie, I think I even said to myself once, “My preparation today is to be unprepared.” When we did this movie – the [Duplass Brothers] wrote a pretty good script, but they didn’t want to do the dialogue. They said, “Yeah, we don’t want to do that. We’ll accomplish the same thing in the scene, but just say whatever you want. Just go with your instincts and be honest. We just want this to be organic. Don’t worry about what the script says.” That was scary and also thrilling, and I think that it made a really good movie. I think it looks like people are really talking to each other, and not repeating lines that they’ve memorized.

Can you describe a little bit more how the Duplass Brothers work together? Do they have separate jobs on set?

They do have separate jobs, but they do a lot of the same things. Mark tends to be more interfacing with the actors, and creative stuff. Jay operates the camera a lot of the time, so there’s that. Then, I would often talk to Jay about the character, and Mark would be helping design the shots. They really are symbiotic. When it came time for big decisions, it was always a tight collaboration for them. We’d shoot this on digital video so we’d do these long takes, improvise for a long time and move around these rooms, and then Jay and Mark would go off and talk to each other alone for twenty minutes. Which is really weird. The crew on this movie were like, “The directors are going where? Down the block?” They just talked and processed what happened. And that’s one reason why I wanted to do the movie, because I heard they worked like that. I heard they just sorta work on a scene and try to come to it in an organic way. And at the end of the day, they’ll re-view it, and that changes tomorrow’s point of view. We shot pretty much in order, which is also nice, and doesn’t happen with movies. We could literally build the story in an organic way, we didn’t shoot the ending in the first week etc. It has a lot of emotional truth to it, the movie.

When improvising in a movie like Cyrus, is there a certain art to when and when not to use a cuss word? And, where did the line "I'm like Shrek" come from?

Yeah, that was just me. It came from my own lack of self-esteem. It’s more of a natural thing [swearing]. In the back of your mind you’re thinking “Well, someone is counting the swear words.” Because once you get more than seven f**ks you’re NC-17; I don’t really know the formulas. I am just trying to be as honest as possible. If that involves swearing, then so f**king be it.

What kind of character do you think you'd like to play that you haven't played yet?

It’s so random, the things that come my way. It’s a little bit like, pointing in the dark. The things that I’m personally interested are books about explorers. I got on this extreme adventure jag in my reading, I’m reading books about Shackleton and Col. Percy Faucet, etc. I’m just really into explorers and sailors. I’ve always wanted to play a priest. Growing up a catholic, I’ve thought there’s something interesting there.

With a cast that includes Marissa Tomei, Jonah Hill and yourself, was there any intention when making the film to bridge "mumblecore" into the mainstream?

First of all, I have met Joe Swanberg, I know Greta Gerwig pretty well, I know Mark and Jay pretty well now, and not one of them would admit to being mumblecore. They hate that name.

What would they prefer?

I don’t know. They just make movies. As filmmakers, they hate that label. Or, maybe they’ve come to love it. I don’t think it was like “let’s bring our movement to the masses,” I think Mark and Jay were like “This is the next step for us. Movies are smaller. We want to do more movies. We want more people seeing them.” I don’t think they felt it was a compromise doing a movie in this way, they got actors they loved, and they still got to work in the way that they’ve always worked. Letting these guys do a movie in the studio is like letting a fox into the hen house. I think they made an accessible movie that is very original and very honest, which is not easy to do.

You seem to be reaching out constantly to the 15-25 male demographic.

Those are the people who go see movies. I’ve always been someone who reached out to younger people. My whole life I was more apt to treat younger people as equal. As an artist, you want to stay relevant. And do work that is exciting and interesting, and if you’re doing that then people want to watch it. That stuff that I’ve done with Tim and Eric [from Adult Swim] that’s the stuff that they mention. Even more so than Talladega Nights: The Ballad of Ricky Bobby or Step Brothers, people are clued into that. I think it has to do with the sense of discovery, that it’s not being shoveled or packaged or sold. You can just go onto your computer and find it or not. There’s something exciting about how weird that stuff is. And I’m a huge Tim and Eric fan myself. They’re good friends of mine. I think they’re the funniest people out there now. I think in ten years, people will look at them like we looked back at Monty Python and think, “What the hell are those guys doing?” It’s still weird. We’re gonna do a movie together, they wrote it. It should be good.

Will Dr. Steve Brule be in it?

No.