LOS ANGELES—At a media event in a downtown hotel, the stars of Paul Thomas Anderson’s Inherent Vice get rolled out one by one to face a table of journalists. They are escorted in and out by publicists who stay for the length of the interview and keep close tabs on the time allotted and the questions asked. It’s a normal procedure that’s followed to a T by everyone in attendance. Everyone except Joaquin Phoenix, that is. The reclusive actor breezes in unattended, as if casually entering the house of an old friend. He’s wearing a plain white shirt with an unbuttoned flannel top and sunglasses hanging off the neckline, and when he reaches his chair he begins the proceedings with “All right—shoot, kill.”

Inherent Vice, opening Friday (January 9), is adapted from the novel of the same name by Thomas Pynchon and revolves around Larry “Doc” Sportello (Phoenix), a half-baked private eye in the early ’70s who jumps to work when his ex, Shasta Fay Hepworth (Katherine Waterston), goes missing. It’s the first film adaptation of a Pynchon novel, partly because the author’s works are unabashedly bizarre. Inherent Vice is no different, which probably explains why Phoenix was attracted to it.

He’s also in practically every scene of the almost two-and-a-half-hour film. When he’s asked at what point he felt like he had fully captured the character, the actor responds quickly. “I don’t think I ever did,” he says in a raspy tone. “I don’t think I ever have felt that way with a character, and I feel like it’s something that I don’t want to do, because I feel like when you become, like, rigid and you go, ‘Well, this is who my character is,’ then it stops being real. Because I don’t think we’re like that in real life. We may have something that we present to others, but I feel like that’s always a problem with a lot of performances, they are locked with an idea of ‘This is who my character is.’ And so I’ve tried to be malleable and take on new ideas. Part of it is just fucking luck.”

No, Phoenix is not your typical Hollywood star and he doesn’t pretend otherwise. At one moment in the interview the Puerto Rican–born actor is told that one of his costars complimented his work earlier in the day, an anecdote he meets with a scoff: “First, I’ll just say that when you come in to do interviews you try to say things that are nice about the other actors. You try and say things like ‘They’re so good, they change on such a cellular level.’ Which is very sweet of her, but I don’t think that’s true. I’m just like a monkey stumbling around trying to say some lines.”

Phoenix has gained acclaim and Academy Award nominations for roles that are unequivocally brave, like those in The Master and Walk the Line. But the bigger he gets, the more apparent his ambition becomes. In last year’s Her, probably his bravest performance yet, the actor was alone on-screen for most of the film. “I do like working with other actors—well, that’s not true, I prefer working alone, but if you are to work with other actors, working with this cast is a dream,” he says, trailing off and then miming the action of jerking off.

When there’s a lull in the questions being fired at him and Phoenix feels enough time has passed, he gets up and walks out, leaving us speechless, wondering if what we’ve just experienced really did happen.