The least Hollywood director in Hollywood talks about the process of creating his latest film, surviving outside the system, and communing with his mother’s spirit. At least, he’s fairly sure it was hers.

There is a story the director Mike Mills tells about an encounter, six years past, with an old friend who is now dead. It was just after the premiere at the Toronto Film Festival of Mills’s surreally comic, autobiographical second film, Beginners, which Mills wrote following the death of his father, who late in life came out as gay. In the movie, Christopher Plummer played Mills’s father; Ewan McGregor played Mills, more or less. The Shetland sweater McGregor wears onscreen was Mills’s own. The graffiti the character writes on the sides of Los Angeles buildings; the drawings he does at his job as a graphic designer; the art on his wall—all belonged to Mills in real life. One running joke in Beginners concerns the Mills character’s inability to deliver album artwork that he’s been commissioned to draw. The band, called the Sads (a real band, impersonated by actors in the film), just want a portrait. Instead, a depressed McGregor draws a whole history of sadness, after which he is fired.

One of the first people Mills saw in the audience after the movie ended was the Beastie Boys’ Adam Yauch. Mills, who is 50, has been making things for decades — drawings, music videos, television commercials, t-shirts, documentaries—and had known Yauch, in one way or another, for a long time. Yauch was moved, Mills says. “He was sort of teary-eyed. I was like, ‘Okay, this is good!’” Shortly thereafter, Yauch asked Mills if he’d design the cover for the Beastie Boys’ latest—and, as it turned out after Yauch’s death from cancer in 2012, final— record, Hot Sauce Committee Part Two. Mills thought about it, gave him some ideas. Yauch wasn’t sure; maybe Mills should just draw their portraits instead? Mills laughed. Then Yauch laughed too. “He was like, ‘Wait a second. I’m doing it, aren’t I? Like, I’m doing exactly what was in your movie.’ I was like, ‘Eh, that’s okay. I get it.’”

In the years since Beginners, Mills has gotten used to this sort of thing: his life and his movies blending so closely that one starts to trade places with the other. Beginners finally won Christopher Plummer an Oscar, and elevated Mills from a cult favorite to a director who could choose his next project. It also turned Mills into a guy who couldn’t walk around Los Angeles without strangers coming up to him as if they knew him. He’d made a movie about his life that completely changed what that life was, or could be.

Beginners is sad, hilarious, deeply romantic. It’s full of grief and love. “Of all the things I ever made in my life, it was one of the more successful, in terms of really connecting with other people,” Mills says now. “And I think it was because it was basically real things. Things that don’t neatly fit into a story. All over the place, people in Japan and people in Minneapolis and people in suburban Atlanta talked about that. So it made me braver. Like, ‘I like this.’ Maybe I could do it again. And people are always like, ‘Oh, your dad dying, that must have been the biggest thing that ever happened.’ I was like, ‘Actually, my mom dying was the biggest thing that ever happened to me’.” He started wondering what a movie about that might look like.

“The ad thing—I have very mixed feelings about it, in terms of my relationship to capitalism and inequity abuse and America. But it’s fucking been really good for me as a director.”

Six years later, we have an answer. His new film, the radiant 20th Century Women, is shot on the same dreamy Santa Barbara streets where Mills grew up. It tells the story of an intimidating and inspiring woman named Dorothea, played by Annette Bening, who shares almost every particular with Mills’s own mother, who died in 1999. In the film, Bening is “wearing my mom’s jewelry,” Mills says, “laying out my mom’s tablecloths, smoking like my mom did, with a black and white cat like my mom had. You know, thinking thoughts that are like my mom’s, talking like my mom did, all that kind of stuff.”