"A lot of people in this business look for validation from the public to feel good about themselves," he says matter of factly, lighting another in an endless string of cigarettes.

"I don't feel that need. I made a conscious decision years ago not to try to let fame or public attention influence what I do as an actor."

Talk of fame, we learn, is difficult for a man who has built his art on disappearing.

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HAVING spent maybe a couple of hundred hours with Cash between that grim morning at Folsom prison and the time I watched him perform at a neighborhood barn dance in Virginia just before his death in 2003, I was curious about how much Phoenix had in common with him off screen.

Not a lot, it turns out.

Phoenix is considerably shorter and doesn't command attention the way Cash did. He shifts about uncertainly when approached by a fan, not quite sure how to react to the good wishes. It's an awkwardness I've seen in lots of musicians, especially members of the '90s grunge brigade. Phoenix has the natural temperament to play Pearl Jam's Eddie Vedder or the late Kurt Cobain. That leaves him far from Cash, a deeply spiritual man who, while shy, would go out of his way to make fans feel welcome. He wanted to lift people in his music and in his interactions with them.

Cash exuded energy. Phoenix seems to save his for the next role.

Phoenix grew up loving the Beatles and hip-hop, not country music, but he was immediately intrigued by the challenge of playing someone as legendary as the Man in Black, whose music earned him a rare place in both the rock 'n' roll and country music halls of fame.

"That's the way it always works for me," Phoenix says. "I look at the character before I even read the script, to see if there is something unique about him.

"I've done some movies that I'm not all that fond of, but I don't think I did them for the wrong reason. The first time I read the script, I'm not even paying attention to what else is going on, I'm just focusing on that character. I want to see where he's going."

"Walk the Line" director James Mangold had a gut reaction about Phoenix after seeing his photo in a newspaper around the time of "Gladiator."

Mangold, whose credits include "Girl, Interrupted" and "Cop Land," had been thinking about doing a film on Cash for years, but he was hoping for a version that had some of the edgy, psychological wallop of the film "East of Eden." He saw similar themes between Cash's story and Elia Kazan's 1955 film, including forbidden love and the struggle for parental approval.

And for his lead, he wanted the youthful vitality and smoldering intensity of that film's James Dean. Phoenix seemed to fit.

In his first talks with Mangold and "Walk the Line" co-producer Cathy Konrad, Phoenix probed. "Are you doing imitations?" he says he asked the director. "Are you re-creating these historical events? And he said no. He said that if people want to hear Johnny Cash, they can buy his record. If they want to see him, there are documentaries. That gave us a lot of freedom."