A lot has been written about Adam Driver’s face, whose unique physiognomy has the power to turn gifted writers into rhapsodizing Tumblrers. One possessed wordsmith even boasted it “worthy of the Mongolian plains.” However you choose to describe the 33-year-old actor’s mug, one thing is certain: it photographs beautifully. Since making his film debut in Clint Eastwood’s 2011 film J. Edgar, Driver has become perhaps the most in-demand actor in Hollywood, attracting the likes of Steven Spielberg, the Coen brothers, and J.J. Abrams, who cast him as the villain Kylo Ren in his Star Wars reboot. Though Driver’s primarily known for playing emotionally stunted characters, from the Neanderthal-ish Adam Sackler on HBO’s Girls to the volatile Kylo, he is also capable of great restraint.

In Martin Scorsese’s Silence, Driver plays Father Garrpe—one of a pair of Jesuit priests (along with Andrew Garfield) who embark on a journey from their native Portugal to Japan in search of Father Ferreira (Liam Neeson), their mentor who is rumored to have committed apostasy. The film is set during the time of the Kakure Kirishitan, a 17th century movement of “hidden” Christians who were persecuted under the Tokugawa shogunate. And Driver is excellent in the film, exhibiting quiet courage—and a stunning body transformation—as the pious Garrpe.

The Daily Beast sat down with Driver in New York to discuss Silence and much more. How long did it take you to prep for the role of Father Garrpe?

I remember we were delayed for six months—I can’t remember why—but in earnest it was about three months getting ready for it, just independently meeting with Father Martin, who was the Jesuit consultant on this, and then the losing weight. Andrew and I took a trip to Wales to go to a Jesuit retreat, and we went to Portugal to tour Jesuit schools. What was the Jesuit retreat like? It was a five-day silent retreat where you’re there with—I shouldn’t say “other Jesuit priests” because we weren’t Jesuit priests and it was glaringly obvious who the actors were, as we were the youngest people there by far—but it was good. I’d been on a silent retreat before at [Juilliard] and it’s a rare time to not have to or feel obligated to talk to anybody, be on your own journey, reflect, read, sleep, run, and go for walks around the grounds. It focuses you. It even takes a couple of days to get out of your city mode and adjust, but then once you do, you’re not anxious to go back to talking.

You lost a tremendous amount of weight for this—51 pounds. How long did it take you to drop the weight, and how did you do it?

It took five months total. The first thirty or so pounds took a couple of months, and then over the course of filming the movie I tried to drop as much as I could. My diet consisted of a lot of steamed vegetables, but it was also a lot of running—seven miles a day, or I had a stationary bike in my room where I’d throw sweats on and bike 40 miles. It was not eating a lot food, drinking a lot of water, taking water pills, drinking a lot of coffee, chewing a lot of gums, drinking a lot of smoothies, and timing meals properly so you could have energy when you needed it or get some sleep.

What did Scorsese say when you showed up on set looking so gaunt?

They were worried! They were worried. But it made sense for the story, and that was the priority. He asked us to lose weight and didn’t have a number in mind, but the story really dictated how much weight we lost—that they’d been on a boat suffering from disease and starvation for two years trying to get from Lisbon to Japan, and we find them at the last leg of their trip at Macau. We wanted the audience to see that journey physically, and then how it went south from there.

So you had to go from your normal body, down to this, and then back up to your Girls and Kylo Ren weight. That’s a pretty crazy yo-yo.

Yeah, it was. It takes a while longer to put the weight back on, but your body swells—it starts to absorb a bunch of water—so it artificially looks fuller than what it is for a while, and you’re eating a bunch of carbs because you can’t really process meat. If you watch Girls, I think it’s the fourth or fifth season, I’m wearing a lot of thick sweaters and was just eating constantly between takes. My first meal back, when I could finally eat normally again, I had a large pizza, and I wanted to try something local so I had duck tongue at this night market, lots of cereal, and donuts. I ate all that stuff all night. And I was definitely in pain after! I’d never felt my stomach stretch that much in my life.

Did making this film force you to confront your own faith? When I profiled you for Newsweek years back we discussed your upbringing—including your stepfather, a Baptist preacher, and how you rebelled against organized religion a bit.

I was raised in the church so I’m very aware of the guilt—not that you have to be raised in the church to understand guilt—and the faith part of it. But for me, even though religion is the boundaries of this movie, it really could be seen as anything—any commitment you make in your life, whether it’s as a writer, actor, or husband. You’re filled with doubt, you get older, you have different experiences, and then you have to reevaluate what they mean to you. One can’t just maintain a childlike faith throughout their life. You can’t answer all questions of the unknown with well, I’ll just have faith. Life requires you to always reevaluate or reassess what you’re doing, if it’s helpful or if it’s not helpful, and that idea makes total sense to me.

Was there a moment in your life where you really questioned your faith? Perhaps when you broke your sternum and had to be medically discharged from the Marines?

That was more of a moment of clarity. It’s hard to pinpoint one thing where my faith has been questioned. I don’t know about religion—I’m not a religious person—but in acting it’s constant. You doubt if you’re making the material make sense, if you’ve made the right choices for your character or in the project that you pick. It’s filled with second-guessing.

Like Silence, there is a religiosity and spirituality to Star Wars that allows it to transcend its genre trappings.

I definitively see that. There’s also the element of persecution. George Lucas originally wrote Star Wars in response to what was going on with Vietnam, where you have a huge superpower fighting a resistance. There’s also Nazi imagery and dogfights related to World War II. With Silence its similar. The Japanese government looked around and didn’t feel like they saw themselves in their culture anymore and felt like it was slipping away, so they wanted to reclaim that—even if it meant persecuting people and killing them. They were government-funded, so felt they were morally justified in oppressing people, and using any means at their disposal to accomplish their aims. Also, both sides felt they were absolutely correct. In that way, Silence and Star Wars are similar.

That element is very interesting in Silence—which side is in the right—because there’s a lot of grey area there. Yes, the Japanese government is wrong to be oppressing and executing Christians, but there’s also a troubling colonialist aspect to missionary work where these people are entering exotic countries and converting people to their way of thinking.

Yeah, of course. One reason why Jesuits were so successful was adopting a culture. They weren’t so direct with imposing their western idea of how to worship on the Japanese, but would adapt the culture and through their common language bear witness. The first time I went to Sundance I caught Brick and came away very impressed with Rian Johnson. What was it like working with him on Star Wars: Episode VIII?

He’s a brilliant filmmaker. And he wrote the script also, and he understands the importance of ambiguity and nuance. He wrote something that I think is remarkable.

Do you ever step outside of your body and just geek out thinking, shit, I’m the villain of the new Star Wars franchise?

It is a trip! I’m not very good at analyzing it, I guess, or even making time to attach meaning to it. So much of it is luck, and timing. I work hard but I can work hard in a vacuum. I’ve been lucky to get these opportunities. It’s very surreal to me. In working on the jobs—and actually doing the thing—I block that stuff from my mind as much as possible, because it’s not good to get nostalgic or overthink it. That might be a good strength of mine: not thinking a lot. [Laughs]

You also wrapped shooting on the final season of Girls, which served as a pretty important springboard for you. What was it like to close that chapter of your life?

It’s bittersweet. I’ve been shooting that for the past six years and have spent the latter part of my twenties doing that job with those people. Because we shoot it in the summer it hasn’t quite hit me yet, but next summer when I don’t have a job and am not seeing those people it will probably hit me. Even now when we talk about it’s that thing we did, which is a strange thing to process. I haven’t had much time to think about what it all means, but it was a great job with great people. I loved every minute of it.