Few of the sloths that end up at the La Brea Tar Pits could be called lucky, given how many of them perished there in prehistoric sludge. Still, the sloth that Ezra Miller is examining looks awfully happy. It is stuffed, smiling, and hangs from a pole in the tar-pits gift shop, and Miller’s bandmates Lilah Larson and Josh Aubin are goading him into a purchase.

“You’re getting one,” says Larson. “You have to!” Miller, she has told me, is something of a stuffed-sloth aficionado.

“I’m gonna let you know how deep this addiction is,” Miller says, unfastening the sloth’s Velcro paws. “I already have this exact stuffed animal.” Still, he buys it. As Miller clasps the sloth’s arms around his neck and wears it like a particularly eccentric piece of jewelry, he announces, “I’m naming him Richard Jenkins, after the actor Richard Jenkins.”

Most movie stars, if asked to traipse through a public place like the La Brea Tar Pits with a journalist in tow, would pull a ball cap down low and try their best to disappear into the crowd. Ezra Miller, who wears a striking green cloak, a sloth necklace named for a two-time Oscar nominee, and happily hums a Taylor Swift song as he peers at prehistoric penis bones, is not such a movie star. He is angular and undeodorized, up-and-coming and proudly bisexual, an alternative to the sea of endless Hollywood Chrises, who might also have the stuff to supplant them. The 25-year-old stole last year’s Justice League with his chatty, cheerfully improvised take on the Flash, and though he also appeared in Fantastic Beasts and Where to Find Them as a downcast young wizard and will reprise that role in this winter’s sequel, Miller may still be best known to film buffs as the wicked son from We Need to Talk About Kevin. Those characters couldn’t be more different from one another, but whatever fundamental part of himself Miller pulls them from is fascinating.

What keeps Miller so honest and emotionally vivid, whether he is starring in a small film or speeding through massive tentpoles? In large part, it is Larson, whom Miller has known since middle school, and with whom he started the band Sons of an Illustrious Father. She is as sincere as her singing voice, the kind of person you simply can’t bullshit. Miller will tell you that she is the cool one in their band, and he’s right, but it’s an unadorned, makeup-free coolness: You want to impress her by being the most real version of yourself. Miller calls her “Dad,” which is one of the few labels Larson likes. “I very much enjoy ambiguity,” she says. “I think most of the things that people inflict upon themselves, the suffering that they choose, is based on restriction.”

“Or what they’ve convinced themselves they have to be,” adds Miller. “We’re all going to die, and at that point, we will be none of those things.”

Casual profundities come easily to this crew, and they also dot Sons of an Illustrious Father’s new album Deus Sex Machina: Or, Moving Slowly Beyond Nikola Tesla, the kind of title that weeds out the people that it isn’t for. The Sons’ songs are sprawling midnight conversations set to music: confessional, philosophical, and emotional. “I think part of our process sometimes feels like therapeutic time travel,” explains Miller. “It’s like trying to write the music that we needed a while ago, then attempting to somehow play it for our younger selves.”

The first song on the album, an anthemic banger called “U.S. Gay,” features a defiant Miller singing, “I want ‘fag’ tattooed in red on my forehead,” the sort of line that’s all the more bracing when you hear it come from a Hollywood superhero. “It’s an emotional roller coaster of a song,” says Larson, who wrote it as a response to the Pulse nightclub massacre. “Partly, it’s about addressing the actual sense of physical precarity I feel as a queer woman. I don’t often feel very safe, and there have been some scary situations where I’ve been very realistically threatened because of my gender presentation and sexual identity.”

“We’ve been in some of those situations together, where my friends have stood between me and a violent aggressor,” Miller says, recalling a night when a man chased him and his bandmates outside their concert venue until Larson turned the tables. “It was a really moving moment in my life,” says Miller. “I wanted so badly for everyone to be out of danger, but Lilah turned around and put her finger in this guy’s chest and said, ‘Stop.’ And he did. It was really, really powerful.”

“I don’t think it was a totally conscious decision,” says Larson. “It was just the ferocity of love: One of my bear cubs was being threatened, and I went mama bear and attacked.” What had motivated the man to chase them in the first place? “Well, I think in this instance, he was turned on,” Larson says. “Ezra looked really fucking good in his tight floral short-overalls and no shirt under it, and I think this dude was really angry about how that made him feel.”

“Thanks, baby,” says Miller. We are now trying to stir tubs of heavy tar, and though Miller is slight of frame, he manages it with far more strength than I can muster. He jokes, “We’ve been training in the martial arts in preparation for our next confrontations with people who are afraid and turned on.”

When Josh Aubin met Miller and Larson several years ago, he found the pair to be high-spirited and also high on spirits. “They were drinking a lot of Four Loko and energy drinks and crying and crying and crying,” says Aubin. “And I loved them.”

Aubin was meant to be the band’s touring bassist, but since the day he boarded the blue school-bus that the members of Sons of an Illustrious Father used to criss-cross the country, he has never left. Aubin is bearded and quieter than his bandmates, but it’s clear that spending the last few years with Miller and Larson has had a profound effect on him. “It’s like any process of finding life partners or people where you can comfortably be yourself,” Aubin says. “If you’re not born with the proper atmosphere to really identify who you are, you’re not going to be able to find that identity within the people surrounding you. Sometimes it takes a long time.”

The members of Sons of an Illustrious Father will often hand off sentences to each other like a baton, and life experiences are treated the same way, where one person’s breakthrough will ripple beneficially through the other two bandmates. “It’s helped me understand myself in ways that I hadn’t really considered, in my sexuality and gender, even,” says Aubin. “I went through most of my life just understanding myself as a straight person, and that’s largely what I’m still understood as, but I’m going back and seeing how that’s not really what has been the actual situation within myself in the past. Not knowing what those feelings are at the time really makes you more confused and more lost, you know?”

Still, life in Sons of an Illustrious Father was not always so harmonious and self-actualized. “We’re a lot better to each other than when we were miserable teenagers,” says Larson, who began the band during a rough period where she was also curtailing contact with her father. “The band family really got me through it, but also took a lot of abuse because I was so angry and despondent. And I took that out on Ezra.”

“It’s hard to talk about your fear, even to people really close to you,” Miller says, adding that he spent years wrestling with issues he has not spoken about publicly until now. “I think there was a lot of mental illness that I did not know how to manage or deal with in the earliest times of the band. I was 15 or 16, I didn’t have any real means of monitoring myself, and I was also working in film and having this strange type of exposure. I was feeling insecure about that relationship to the world and what it would actually mean for me, I was feeling insecure in my decisions up to that point to take that path, and I was feeling insecure about the ways it held the potential to really separate me from people I love. That was tied into the illness that I was discovering in myself.”

Fights among the band members were frequent. “We definitely fell into a deep familial love when we first met each other,” says Aubin, “but there was also the level to which Ezra’s manicness triggered stuff in me where we really collided a lot in terrible ways.”

“I didn’t want to acknowledge that I was trying to blaze a trail that was hurtful or harmful to myself and others,” says Miller. “I didn’t want to hear it from anyone. Didn’t even want to hear it from myself.” What changed? “I think, as is often true in cascading deteriorations, I hit walls, and I felt them, and there were people who I loved who were there to both catch me and point out to me that I had just been running towards a wall, and that’s why I had collided with one.”

Eventually, Miller says, “I discovered that there were things in this world that I did want to experience and know and share, that I didn’t want to be a lone pioneer, an individual hero exploring uncharted territory at every moment of my life.” Still, he doesn’t want to simplify his relationship to mental illness: “To say that there was even a series of turning points would be to disassociate myself from the continuation of that struggle in my life, which I don’t. If there’s a difference, it’s a major one between the space where you don’t even want to hear the voice inside yourself tell you that anything is wrong with who you are, to the space where you can really embrace that there’s a lot wrong with who you are but that doesn’t mean that it’s wrong for you to exist or to be here or to be alive. It doesn’t mean you don’t deserve love or connection or even, dare I say, moments of stability and joy.”

Larson is beaming as Miller talks. “I’ve watched him navigate this with great pride and admiration,” she says.

“Thanks, Dad,” replies Miller. He is unbothered by what Hollywood might make of his revelation. “These days, I’m stoked to talk about it. Everyone experiences some gradation of these sorts of struggles and questions, and I think the more we can cradle our own demons and let them die in our arms, the more we can offer that care for other people.”

Larson jumps in: “I thought you were going to say, The more we can offer the corpse of a demon to each other.”

“Honestly, Lilah, I rock with that metaphor,” Miller says, workshopping it out loud. “You can be like, ‘Here’s my demon corpse, which I keep wrapped around my neck. I notice you have a living one that’s gnawing on your earlobe. Should we trade Pokémon here?’”

“It’s almost there,” laughs Larson. “The metaphor is almost there.”

In front of a green screen at the Tar Pits, a photographer takes our picture. She will Photoshop us into several prehistoric scenarios: In one photo, the band is running from dire wolves, and in another, Miller tries to save me as I sink into sludge. When I first met Miller on the set of Justice League two years ago, the entire London set was wrapped in green screen. Has the one at the Tar Pits given him flashbacks? “And flash-forwards,” he says with a wink. Warner Bros. is still trying to mount a stand-alone Flash vehicle, and Miller now regularly makes big-budget casting shortlists with the A-list likes of Ryan Gosling and Donald Glover. He will bring his unique reality to whatever Hollywood can create in a computer.

After we get our photos, the band departs to prep for their concert at the Hollywood club Bardot. When I join them that night, the crowd is filled with young people who already know the words to “U.S. Gay” and sing along as Miller belts out his part of the queer anthem. (One swaying concertgoer wears a Flash helmet.) Near the end of the show, the band members step away from their instruments to perform an a cappella cover, and Miller and Larson close their eyes as Aubin puts his hands over his heart. “I’m not a woman,” they sing. “I’m not a man. I am something that you’ll never understand.”

They are performing Prince’s “I Would Die 4 U,” a song steeped in the sort of ambiguity and intensity that comes easily to the members of Sons of an Illustrious Father. As the chorus nears, they turn away from the audience and face each other, offering the lyrics as a covenant: “You,” croons Miller, staring at his bandmates. “I would die for … you.” Behind them, perched on an amp, Richard Jenkins watches his new family sing their hearts out, still smiling that contented smile.