Nature Boys

They're both rich and famous, they're both notoriously earnest and left-leaning, they both have reputations for being emotionally tortured. So it makes a kind of cosmic sense that Sean Penn and Pearl Jam front man Eddie Vedder would be friends; they have been since 1995, when Vedder wrote music for Dead Man Walking, in which Penn starred. Both are currently experiencing second acts, Penn as a director and Vedder as a film composer. The duo have now collaborated: Vedder has written the sound track for Penn's movie Into the Wild, based on the book by Jon Krakauer. Later this month Vedder will release a CD of songs written for or inspired by the movie, the closest thing to a solo album he's ever done.

Into the Wild is the true story of Chris McCandless, a good kid from a prosperous but unhappy family, who left home, burned his money, changed his name to Alexander Supertramp and in 1992 walked off into the Alaskan wilderness. He died there of starvation 16 weeks after he arrived. What was he looking for? Penn and Vedder--who are a lot funnier than they get credit for--talked to TIME'S LEV GROSSMAN about this and other profound questions, like how you keep a huge grizzly bear happy on a movie set.

TIME: What made you pick up Krakauer's book?

PENN: The cover grabbed me--the bus, the image of the bus with the title Into the Wild on it. I've made a lot of decisions in my life that you could call judging a book by its cover. And I've become a real advocate of it. So I took the book home, and I read it cover to cover twice, and I went to sleep in the wee hours and immediately got up in the morning, and I saw in essence the movie that you saw last night.

What was it about what McCandless did that got to you?

PENN: I really think that we shouldn't just accept rites-of-passage opportunities as they come, because what we'll find is that they don't come in our world anymore. And we shouldn't look at them as a kind of luxury or romantic dream but as something vital to being alive. McCandless quotes somebody else in the movie: "If just once you put yourself in the most ancient of circumstances ..." This is where nature comes into it--and I think that Eddie and I share this feeling--that every sober-minded person of any belief would probably agree that the biggest issue is quality of life. You've gotta feel your own life to have a quality of life, and our own inauthenticity, our corruptions, get in the way of that. The wilderness is relentlessly authentic.

Have you ever gone through anything like that? A rite of passage?

PENN: Formatively the experience I had, where I found the beginning of the map to figure out how to feel my own life, would have come from surfing as a kid. My wilderness is the ocean, and my experience with risk and conquering fear was the ocean.

Being alone like that can help people find themselves, but it can also make them fall apart.

VEDDER: See, I love it. I need it. I'm a better person because of it. I mean, I feel really blessed even to have had the opportunity of disappearing on an island or something and not seeing anybody for weeks. It makes me somebody that somebody else could live with. That's another thing, when you talk about the environment and how precious it is: it makes us better people.

How did you get into doing sound tracks, what with being a huge rock star and all? Is it a lot different from doing Pearl Jam?

VEDDER: Yeah, it's easy. Really. I almost don't remember a thing. It was like I kinda went into some weird space for a week or two, and then I woke up out of this daze, and it was done. I don't really remember it.

That doesn't even sound like work.

VEDDER: I was thinking about it yesterday. I don't trust art that was made easy. If there's not some kind of pain involved, then I don't trust it. And I thought, Well, how can I be honest and tell people that it was easy? But what I figured out is that the hard part was 25 years ago, when I went through what this kid went through. I went through pain, but it was just a long time ago. And I guess what's a little bit worrisome to me is how easy it was to access it. You know? That I just had to barely put my finger in. It was right there on the surface. I thought I'd grown up much more. I'm glad there was a use for it, but now I've got to tuck it away again.

So how does it work? Sean, do you just go to Eddie and say, "Here's a bit with a guy hitchhiking. Write a song that would sound good with that"?

PENN: Well, I'd written the script originally structured for songs. I love that kind of thing in movies. I was born in 1960, so you can do the math and figure out that I was just coming into my own with Harold and Maude, and earlier than that, Simon and Garfunkel and The Graduate, and Coming Home. It just added something, letting your songwriter be a co-author of the script in many ways.

VEDDER: It was like a factory, where I would sit in a chair and they'd hand me instruments. We'd just keep going, and I didn't have to teach anybody the part or talk them into the idea, the theory, the soul of whatever the piece was. I'd just sit in the chair, and they'd hand me a fretless bass, and they'd hand me a mandolin, and they'd take a second to do the rough mix, and then I'd write the vocal, and it was just quick. It was as in the moment as you could be, and in that way it's like a great feeling of being alive. You'd hear two pieces at the end of the day--or three--and feel like you were actually doing something on this planet while you were here.

Some of the vocals were wordless, just these howling chants ...

VEDDER: That was all stuff I did not-to-picture. In a way--like the music for the scene on the mountaintop--I don't think I would have done that [if I had seen the footage]. I would have felt too--like if you could be both vulnerable and pretentious at the same time?

PENN: [Laughs.] Leave that to me!

Emile Hirsch [who plays McCandless] goes through a truly shocking physical transformation to show McCandless starving to death. How'd you achieve that?

PENN: Turns out he has phenomenal willpower. A 21-year-old kid, who just got the right to go drinking with the guys in the bar, and he is by choice sober. By choice a monk for eight months. He was in a room watching his feet roll under him on a treadmill or doing pushups or eating another glass of water with lemon in it for dinner every night for eight months. You know, that's really, really hard.

He has a scene with a bear that got some audible gasps.

PENN: He was an 8-ft. 6-in. grizzly bear, and if he wasn't a good bear, I wouldn't be here right now. But no flinching from Emile--he just stood there, six inches away from that thing.

What do you do when the bear's not being a good bear?