When we meet at the Cannes Film Festival, Swinton tells me that she tries to seek out opportunities to "give something authentic". Some parts make this easier than others. She recalls that when she played a pregnant mother in Tim Roth's 1999 incest drama, , she was actually pregnant herself, "and in no position to contribute anything to any film, frankly. I was about to give birth so it was the only film that I could contribute anything to, because what I was being required to contribute was the authentic thing."

Her casting as the evergreen Eve is perfect, because time appears to have really stood still for Swinton. At 53, her translucent skin and angular Bowie-esque physiognomy have changed little since our first encounter, 13 years ago. In fact, so kind have the years been to Swinton that I start to wonder whether she isn't a real-life Dorian Gray.

"I do feel like I have lived for several centuries," she says. "Even if it's short, life's long. So Eve wasn't a stretch for me. But at the same time, of course, these immortals know they're not going to die; I'm clear that I am. But then there's an element in which all artists never do. So that felt familiar, too."

Eve is an optimist who sees the blood-bag as half full (biting necks is so archaic), while her depressed rock-star husband, Adam (Tom Hiddleston), grumbles morosely about the damage "Zombies" (we mortals) are doing to the world. She is living in bustling Tangier; he's holed-up in Detroit. To him, the Motor City is a hollowed-out shell, a shadow of its former self; to Eve, who goes there to pull him out of his latest funk, it's an "abundant wilderness".

"It's exactly how I felt about it," Swinton enthuses. "For half a day you notice that the buildings are crumbling and empty, and then after about four hours you notice that the grass is up to your waist, there are incredible plants. Then you slowly notice that people are inaugurating urban farms, and they're starting to barter with each other. I find that all really inspiring and exciting. One man's decay is another man's life."

She makes Detroit sound like a metaphor for the film, which she characterises as "about survival, and about how we go on living". For her, it is also about death and its legacy. "While we were making this film, my mother was dying. Which is why this film is about dying for me. How do we die? How do we prepare to die? For me it's a question," Swinton says.

Another major death came early in her career, when Derek Jarman passed away in 1994. It was the filmmaker-polymath who gave Swinton - who was working unhappily in theatre at the time - her first film role, as a model in ; she worked with him "almost exclusively" for eight years. They made seven films, and she experienced the loss deeply. "He was a very good friend of mine so I miss him," she says. "If we'd made one film together, it might have been less hard. But I thought it was always going to be like that, nutcase that I was."

By "like that" she means sitting at a kitchen table with someone for years, creating work from a shared sensibility. This is still important to her. She has done big "industrial films" where she has felt like a "spy", but Swinton's real home is smaller, more personal, often "painfully long-term projects", developed closely with directors with whom she has built a relationship.

She looks for kindred spirits, and can often sense them from a distance. Even before she encountered Jarmusch in person - backstage at a Darkness gig in Los Angeles - "he felt so familiar".

Swinton remembers watching his 1984 work as a student, and feeling that it was "absolutely the first American independent film that felt like it was America from a stranger's point of view. He's always felt like he's got this alien view, and I've always cleaved to that. I've always thought, 'Yeah, I recognise that. You're a brother.' So it was only a matter of time before we met."

The same is true of David Bowie. As a 12-year-old, and feeling, she has said, like "a square sort of kid in a round-pond sort of childhood", Swinton carried around a copy of because the pop icon's appearance on the album's sleeve made him look like "a close imaginary cousin and companion of choice".

She eventually met him in London, and last year appeared as his wife in the music video for his single, . Many people thought Bowie had retired due to ill health and his sudden re-emergence with a new album, , took everyone by surprise. "The thing is that people do go on living even if you're not hearing about them," Swinton says.

Still, I tell her, it was inspiring that someone of his stature was able to step out of the information stream that deluges us daily, and keep the project secret until he decided to announce it.

"Of course," she says. "But it's funny, this thing of stepping out, because it's possible to never step in. I do think, though, that it's also possible to be somehow caught up in it and think you can't step out. I don't know, I am truly not in it. I am unplugged."

This is pure Swinton: she has been doing things her own way for years, and probably always will. You can see this in the diversity of her recent work, with such filmmakers as Anderson, Bong, and Jarmusch, with whom she started discussing around eight years ago.

She is making Judd Apatow's , and is in talks to join the cast of by the Coen brothers.

"I don't choose roles, I choose the director," she says. "I choose the conversation with the filmmaker. That's the thing that really needs to last, because one needs to go on being excited to see someone at events like this. I'm really interested in being with friends when I am making a film."