In some ways, Joaquin Phoenix seems the antithesis of a Hollywood star.
Previously reluctant to take part in the awards season circus - memorably calling the Oscars "bulls**t" - his unexpected appearance at this year's Golden Globes prompted a ribbing from host Tina Fey.
Then there's his attitude towards celebrity. Unlikely to be seen snapping selfies at an A-list haunt, this self-confessed "creature of habit" leads a resolutely ordinary life in his resolutely ordinary jeans and scruffy sneakers, spending his time off screen catching up with close friends and family.
Even when it comes to talking about his latest role in Inherent Vice, a time when other stars would happily blow their own trumpets, this chain-smoking actor is stoically pragmatic, unbothered about having his 149 minutes of big screen glory.
Set in Los Angeles in 1970 and also starring Josh Brolin, Owen Wilson and Reese Witherspoon, the quirky crime comedy sees Phoenix's Doc, a barefoot private investigator, go on a trippy journey to find his ex-girlfriend (Katherine Waterston), who has disappeared and left him with a tangle of clues as to her whereabouts.
The movie marks a reunion with Paul Thomas Anderson, who previously directed him in The Master, a film that earned Phoenix an Academy Award nomination in 2013 (he was also nominated in 2006 for the Johnny Cash biopic Walk The Line and in 2001 for his role in Gladiator).
"I enjoy the process so much," explains the actor. "I try to be process orientated, but sometimes it's hard work. If I don't enjoy the process, I don't find it fulfilling.
"But with Paul, even if the movie never even came out, I'm really satisfied. I loved making this movie and that's rare."
Although he was born in Puerto Rico and travelled around Central and South America with his family, who were involved in the Children Of God community, Phoenix, the brother of late Stand By Me actor River, moved to LA when he was six and has lived there ever since.
But the actor, whose mum worked as a secretary at a TV channel ("There's nothing less hippy than being a secretary at NBC!"), feels unqualified to judge whether the Los Angeles of Inherent Vice is true to that time.
"I don't know anything about the Seventies. I don't even know about the current time," says the 40-year-old, laughing. "I don't know that I interact with Los Angeles enough to have an opinion."
If it sounds like he's being stubborn, in person, it doesn't come across that way. If anything, he seems modest and is quick to say when he doesn't feel qualified to opine, prefacing answers by apologising if he's repeating what other actors have said or if he sounds patronising.
Even when he's talking about his own life, a subject he certainly is qualified on, and whether he immerses himself in LA culture, he seems bemused to give his answer.
"I like interacting with my friends," he says. "There are a few restaurants I like to go to and a few parks, but I don't think I really embrace the city as a whole. I'm not out socialising a lot."
Considering his hefty workload, it's probably a good thing that partying is off the agenda. With stellar performances in Her, and spoof documentary I'm Still Here, where he pretended to become a hip-hop artist, Phoenix isn't short of offers.
Putting his enviable roles down to "luck", and describing himself as "realistic" about his career, he has noticed a change in the work he's been offered recently.
"I've been so fortunate," he explains. "There are movies and scripts I read and five years ago I would have worked with, and now... I don't, you know. I'm definitely spoiled."
For now, he's happy to broaden his professional horizons.
"I like all sorts of movies," he says. "I've never not wanted to do a movie because of the genre or the studio. I'm completely open to whatever it might be."
The director, he says, is "the most important" consideration for him when choosing projects - though he couldn't tell you exactly what it is he likes, or doesn't like, about them.
"Sometimes, it's just a feeling," he adds. "It's like when you start dating somebody, there are all these reasons why you like them and it's a leap of faith. Sometimes you get lucky, and sometimes..."
He does admit to becoming less fixed on how he should prepare for roles, though, joking he "just prays for the best".
But ultimately, he says he's been unaware of the profound effect I'm Still Here has had on him.
"This idea that we didn't have any control over what was going to happen when I interacted with the public - it was really having to be malleable and be in the moment.
"That seems an obvious thing for an actor, but I think when you make so many films, and with the kind of inherent rigidity of those films, you lose it in some ways. I want to stay receptive to what's happening in the room and react to that."
Inherent Vice is in cinemas from Friday