It all came down to a 6-year-old Texan named Ellar Coltrane. When the blue-eyed lad auditioned for Richard Linklater in 2002, the writer/director made a risky bet that the unknown child actor was the right kid for Boyhood—a daring, unprecedented project that would film the same people as they aged, in real time, over 12 years. “Child actors have this adult-pleasing personality,” Linklater says. “They are cute kids who are trying to have an effect on you, make you laugh. Ellar wasn’t like that at all. He didn’t give a shit what you thought of him, which was refreshing.”

The R-rated movie, which shot for a few days each year from 2002 to 2013, chronicles the life of Mason (Coltrane) as he navigates the treacherous waters of childhood. We see him shuttle between his divorced parents (Patricia Arquette and Ethan Hawke), he cope with his mother’s remarriages (and the two lowly stepfathers who came with them), endure puberty, discover pot, fall in love, and get his heart broken. It is a grand cinematic experiment from a diector who regularly traffics in them, but none of it would have happened if Coltrane, the son of two Austin-based artists, lost interest or turned into a schmuck. Thankfully for Linklater—and us—he did neither.

While making Boyhood, Hawke, Linklater’s frequent collaborator, watched Coltrane evolve from a self-assured kid into an introspective, soft-spoken young man. The two formed a bond, so Hawke, once a child actor himself, asked to interview his on-screen son for EW. A month before Boyhood’s July 11 opening, the two wiry actors, now 43 and 19, reunited in Los Angeles for a long chat. The first order of business? Shoes off.

Hawke: [barefoot, sitting cross-legged on an ottoman facing Coltrane] A lot of kids go to little theater workshops. You went to the Richard Linklater Cinema Studies class at age 7. And unlike most kids, you have a thesis project to show for the whole deal. Does it feel like that to you?

Coltrane: [Removing his Velcro sandals]: Yeah in a certain way. I was just kind of along for the ride when I was young. I learned gradually by doing it. It’s very strange to have this reflection of all this work that I put a lot of myself into. But I almost didn’t think of it as a [film] project. It was just something that I was doing.

Hawke: But you did think about it. When you were very young, you were always extremely opinionated about movies, books, music. You started to remind me of my friend River Phoenix. He was a really interesting person. How much of your interest in the arts comes from your parents?

Coltrane: I was raised to be some kind of artist. Even before we started filming, I was being pushed to create something. But I also learned a lot from you Rick and Patricia—the method, the long-term nature of this. I learned a lot about patience. And I never thought about this movie coming out.

Hawke: We never talked about it. We did years of work that we knew nobody was going to see until some seemingly fictitious time. When Rick texted me that photo [at the wrap of production in 2013] of you two hugging in the middle of the road in a desert, I kinda fell apart. I couldn’t believe that our secret little project was done. Did it feel like that to you?

Coltrane: Yeah, definitely. It was just this personal experience. That’s what it was for most of us. It was something that we were doing for ourselves.

Hawke: When I was doing Dead Poets Society, I was about the same age that you are right now, and the actor Norman Lloyd said to me, “You have no idea how lucky you are. You guys think you are having a nice time but you don’t know how rare an experience this is.” He was in his 70s and he was saying that [director] Peter Weir is a really rare person, and this experience of making Dead Poets Society [was unique]. And I feel a little way like that towards you. I don’t think you even know how uncommon Rick is.

Coltrane: Yeah, I’m terrified to work on another project.

Hawke: You’ll be profoundly disappointed. [Laughs] The first time I saw Dead Poets Society, I thought it was a good film in the parts I wasn’t in. But every time I came on screen it turned into some home movie and I was hearing a screeching sound, like an alarm. Did you have any feelings like that watching Boyhood? It must have been weirder for you because there was so much of it that you don’t even remember doing.

Coltrane: And so much of myself that I didn’t even know I was putting on screen—especially early on and in the middle years, you don’t have the same self-awareness that you have now. There was just so much of myself that was going on screen. But it’s impossible to really worry about it.

Hawke: If this movie came out when you were 7, you’d be a different person now.

Coltrane: I probably would have lost my mind. Just seeing how much effort it’s taken me to navigate this [publicity campaign] now, I can’t imagine how I would have dealt with it at a younger age.

Hawke: Your parents split up during filming. They handled it better than most, but was it tough for you, especially since divorce figures prominently in the movie?

Coltrane: I became very depressed, and looking back now, I see that. I went to a really dark place, completely as a result of my parents splitting up. Watching the movie, some of the scenes with the stepfathers and the more painful elements of the broken home, I didn’t let myself relate to at the time. But watching it back, it feels very familiar.

Hawke: I think the movie gave your childhood a little more structure than it would have had without it.

Coltrane: Absolutely, it was the only structure, I had, pretty much.

Hawke: Didn’t you get a driver’s license for the movie?

Coltrane: Yes. The art director taught me to drive. [laughs]

Hawke: [laughs] I think I had my first kiss on screen. I had never actually kissed a girl before Amanda Peterson [in 1985’s Explorers].

Coltrane: [The movie was] an entirely different thing in my life—this organized thing that I was consistently working towards. I certainly had no reason to ever stop. Plus, I wasn’t raised in an environment that ever caused me to want to rebel. That’s never been a part of my reality. I feel like that’s so ingrained in so many children that you are so confined and repressed growing up that anything you do, you have to rebel against it at some point.

Hawke: F–k this movie.

Coltrane: [Laughs] Right, and I never felt that way with Boyhood. My parents never forced me to do anything.

EW: What was your childhood outside of this movie like?

Coltrane: Free-form I supposed. My mom comes from a really out-there upbringing so for her the way she raised me is pretty disciplined. I was home-schooled but more really unschooled, really.

Hawke: He was kind of raised by wolves.

Coltrane: That’s what I’ve been saying, that I was left to a pack of wolves.

EW: Are there any specific scenes that really catch you off guard, that are harder for you to watch?

Coltrane: It’s really the end. I don’t feel that emotional during the film. It’s really when the credits roll and it hits—I find myself so engaged. It’s my life in a lot of ways. I don’t feel very emotional in my life very often and so watching it, I’m sucked into my own head and I’m lost in that place. But then when it ends, [I think], ‘Oh that’s a movie, that’s this thing I helped create.’ And that final moment where Mason is, that’s very much where I am now. What’s happening after the credits, [now] that’s my life.

Hawke: A couple of my favorite scenes that I’ve ever been in in my life are with you. The whole dialogue about elves and kissing girls, those are conversations a lot of parents and kids have.

EW: This movie must feel even more personal to you since you collaborated on so much of the story too.

Coltrane: Absolutely. Very little was orchestrated ahead of time by Rick. It was all very organic, especially when I got older. In the same way it’s myself reflected, it’s also an artistic reflection of myself and seeing the first piece of art I’ve followed to the end.

Hawke: The laughter always surprises me throughout the movie. And the fact that people always think something horrible is going to happen, the anxiety.

Coltrane: I don’t think we ever intended that at all.

Hawke: No, we didn’t. But we are so conditioned to seeing horrible things happen in movies. Does this experience make you want to be an actor?

Coltrane: This makes me want to make art. Whatever that is, if acting can be an outlet to that then absolutely.

Hawke: That’s a good answer.

For more on Boyhood, pick up a copy of this week’s Entertainment Weekly, on stands Friday.