A look comes over Brad Pitt when he listens to James Gray that can only be described in one word: tickled.

And a little awed.

Earlier this week, the actor and director visited Washington to premiere “Ad Astra,” a science-fiction drama in which Pitt plays an astronaut sent to Neptune to retrieve his father, who has been presumed dead. Gray conceived his idea in 2011, but it lay dormant until Pitt agreed to produce it in 2016. The film, both agree, changed profoundly in the ensuing years, becoming as much a meditation on middle-aged regret as a speculative glimpse into a space-age future. “It’s a wild horse, and it gets away from you,” says Gray, not just about “Ad Astra” but about every movie he’s tried to wrangle, including 2016’s “The Lost City of Z.” “It’s your job to make it beautiful as it runs away.”

Pitt barks out an admiring laugh at that turn of phrase, which happens frequently in the course of a fast-moving conversation that veers from Pitt’s recent publicity trip to Asia to the state of modern cinema. The two men have been friends since the mid-1990s, Pitt says, and their back-and-forth always loosens him up. “Maybe it’s because James is so forthcoming about his missteps and embarrassments, which opens up a closed-down person like me to be [just] as open.”

Both Gray and Pitt see “Ad Astra” as a way to examine retrograde ideas about masculinity that are being questioned throughout the culture. “We have to redefine it,” Pitt says bluntly of the trope of the cool, emotionally remote hero. His character, Space Command Maj. Roy McBride, is the epitome of macho self-control, until he realizes that the psychological armor he has so carefully maintained has become a handicap.

There are cool space-travel scenes in “Ad Astra,” as well as eye-popping stunts, a battle with pirates on the moon, and a terrifying encounter on a biomedical research craft. But the film’s most impressive special effect might be Pitt himself, who delivers a carefully calibrated performance as a man going through a life-changing catharsis.

Coming on the heels of a similarly accomplished turn in Quentin Tarantino’s “Once Upon a Time in Hollywood,” Pitt’s commanding lead portrayal in “Ad Astra” is all the more stunning for being so restrained and understated. (But please don’t call this year a comeback. “I’m still doing it the same way I’ve always done it,” Pitt insists, saying he usually does one film a year, with occasional breaks. “It’s just kind of cyclical and the way things open up and line up.”)

Watching McBride first cultivate isolation, then break through it, might invite reflexive comparisons to Pitt’s own extreme fame. Although the 55-year-old actor says he’s not as closed-down as McBride (“I’m just not as open as my friend Jimmy James Gray is”), he admits that there are parallels in the overwhelming loneliness of celebrity.

“Certainly when I first started out, I felt lost, not understanding being cut off from the herd,” he says, recalling his breakthrough moment in “Thelma & Louise” in 1991. “I always felt like there should be a manual or some kind of preparation for what it means to lose that kind of freedom, [to be] anonymous on the street.”

Still, Pitt insists, “Ad Astra” is “about more than that.” Recalling the images of masculinity he encountered in his Missouri youth, he says, “It’s the stoic Marlboro Man image that I certainly grew up with, my dad rocked it — he rocked it like a champion. And I think it is exactly what you identify as getting to a certain point in your life and going, ‘It’s just not working anymore. And I’m longing for a greater connection, and I’ve got to see what my part in this is.’ ”

Both Pitt and Gray agree that, had they made “Ad Astra” 20 or even 10 years ago, it might have been a more conventional cool-dude-in-space ad­ven­ture. Instead, it’s very much a late-middle-aged man’s movie, full of self-doubt, grief and uncertainty.

“This was a big part of our conversations,” Pitt says. “Understanding our pasts, what was ours, what was theirs, really digging into that. Which has become Roy’s journey, I think — going to the furthest reaches of the solar system to look at his past, before [he goes] forward in a freer state.”

And, at a time when it’s tricky to be a privileged white guy — especially in Hollywood — “Ad Astra” plays with and punctures assumptions.

“You have to have the myth to destroy it,” Gray says, adding that it was crucial to cast someone of Pitt’s iconographic symbolism — the tall, blond movie idol — to break the myth down. “If we had made the film . . . starring Wallace Shawn, who’s a wonderful actor, there’s no Marlboro Man to destroy.” Gray calls that archetype “a very weird thing, a very toxic thing, a very dangerous thing, actually, for the long term. I think it’s done terrible things for the history of the world. We wanted to try to unpack that a little bit.”

As interested as Pitt is in redefining the male image, he’s also clearly invested in redefining American film. He founded the production company Plan B and has championed such filmmakers as Steve McQueen (“12 Years a Slave”), Barry Jenkins (“Moonlight”) and Ava DuVernay (“Selma”).

What many see as Pitt’s attempt to use his white male privilege for good, he insists, is nothing more than supporting artistic vision and bold storytelling. But there is no doubt that in an industry plagued by vexingly narrow ideas about what auteurs should look like, he and his co-executives have been willing to pull the lens back to an unusual degree.

“It’s our taste,” Pitt explains simply. “It’s our affliction, really. We were weaned on ’70s films. And ’70s films were not black and white. They were very complex and complicated and flawed studies. And it’s what I’m drawn to.”

The ambivalent protagonists of the 1970s — in the films of Sidney Lumet, Alan Pakula and Martin Scorsese — clearly inform Roy McBride in “Ad Astra,” which feels like both a throwback to an earlier, slower, more elegant age and a flag planted for the idea that films can still be ambitious, not just technically but in striking such subdued, contemplative tones.

“It’s curious to me that this film is being called adult cinema,” Pitt says, noting that many of his favorite films to this day are those he saw as a kid. But he wonders whether young people now can tolerate, much less appreciate, the kinds of immersive, slow-burn experiences he still craves, both as an actor and audience member.

“The younger generations receive their information differently. They may have different synapses formed than us. It’s more information, quicker, and they want it in bursts. And I see a lack of patience for sitting in something and letting it open before them. I do wonder what the future is. . . . Now there’s so much material out there fighting for eyeballs.”

Pitt turns to Gray. “What would you say?”

“I have a little bit less optimism than maybe I should about the medium in general,” Gray says thoughtfully. “It’s one of the most remarkable success stories in the history of any art form. . . . Now I worry that it’s almost like the opera. That it has this brief magic moment where it occupies this beautiful place in the culture.” He references the crowds that lined the streets for Verdi’s funeral and that by the 1920s, Puccini died and the medium was “dead in five years.”

“The reason I bring this up is not because I think the cinema is going to die. But we cannot be complacent,” he says. “I hear people say all the time, ‘Art doesn’t die, movies are [always] going to be here.’ Yes, but you have to fight for it. You have to fight for its place in the culture, you have to fight for its relevance, you have to make it happen.”

Pitt has been listening intently. From his vantage point, he says, the fight isn’t for cinema writ large, “it’s just fighting for your project.” As he gets up to leave, he adds a final thought. “And by the way,” he says with a wry, conspiratorial smile, “they are fights.”