Just about the last moviegoer in America who has never seen Diane Keaton on the screen is the insecure, charmingly spacey star herself. That means that Diane has missed both Godfathers (in which she played Michael's WASPy wife) plus the three latest Woody Allen comedies, including his new czarist epic, Love and Death. "I just don't like the way I look and sound," Woody's dazzling deadpan foil explains. Her desperate lack of self-perception is now mercifully in the care of a shrink. "She has no confidence," observes Allen. "If there's a way to twist a compliment into an excuse for self-criticism, she'll find it. Diane," says Woody, not one to squander superlatives, "is one of the greatest natural comediennes I've ever seen."

Offscreen, Allen and Keaton are probably each other's best friend—a relationship that has sometimes gone beyond what Plato had in mind. Johnny Carson, who books Diane on his show, says, "I think she's Woody's sister. Both of them are uncomfortable and withdrawn in a crowd. She's a free spirit—and her vulnerability is a good quality. She's honest about being what she is, and that's rare." (Accounting for her rather giddy talk-show persona, Keaton says, "I'm a little on the manic side because it's live.")

Others before Johnny and Woody have recognized her whimsical temperament. Diane was the one clean jean amongst the tribe of hippies in the rock musical Hair. "I don't think I was meant to be in it," she says now. When the producer made the show nude, she recalls, "I eventually got the lead but kept my clothes on. It was just too mortifying." Diane also subsequently rebuffed a part requiring a nude scene in a Bruce Jay Friedman play. "All I could think of was my agent sitting in the front row. Today, it would be my analyst." In the meantime, the agent got her a presumably more dignified role: as the track-suited housewife on the Hour After Hour deodorant TV spots. They paid upwards of $25,000, more than four times her take from the original Godfather.

Though she is approaching a tax bracket and post-Aquarian age (30 come January) where she should have it all together, Keaton's life is still just a bowl of crunchy granola. Having outgrown chuga-lugging chocolate sauce straight from the can, she now subsists mainly on seeds, nuts and raisins. And her fashion-model looks aside, Diane prefers to plotz around in men's clothes like Ralph Lauren shirts and vests, and the ungainly style of basketball sneaks Woody wore with his dinner jacket squiring Betty Ford to this summer's Martha Graham gala. (Though he was the First Lady's official consort, Woody also dragged along Diane as date, since both Allen and Keaton have studied with Graham.)

Diane now lives in a New York apartment, with a Butterfield-8 address but unpretentious decor. There is a complete photographic darkroom, yet no rugs and a lot of unvarnished furniture. "She's a genuine primitive," Woody reports, "but she reads, she has ideas, and she has a flair for every art. The one drawback is that when I go for a walk with her she stops at garbage cans to fish out things she can later make into collages or furniture and it embarrasses me."

Though she has made New York a natural habitat, Keaton was born in L.A. and first got into the arts and crafts there. Her father is a civil engineer and real-estate broker; her mother a photographer accomplished enough to shoot the dust-jacket portrait for Woody's latest book. Diane suffered three semesters at two California colleges "just to do shows" before dropping out to join Manhattan's Neighborhood Playhouse at 19. Then came Hair, where Allen glommed onto her and cast her both in the Broadway and then film version of Play It Again, Sam. (His previous straight woman had been his ex-wife, Louise Lasser.)

In addition to her Allen and Coppola collaborations, Diane has tried singing in a Greenwich Village boîte in a typically tentative ("I hate actresses who sing") if artful fashion. She recently completed her next movie, a domestic comedy co-starring Elliot Gould. "I'd like to do a film where I could really show something about myself, something with a little more serious context," she now says. "I really don't like the fact that I'm chicken and stay away from situations where I have to take a little risk."

She also shys away from showbiz socializing which she finds "vacuous, moronic." She has no steady romance but continues to see Woody, among others. Her only live-in companion is a cat. Marriage? "I think I'd have to be a little healthier and have a little nicer opinion of myself." But analysis seems to be helping, and perhaps seeing a Keaton film for the first time will provide her a belated epiphany. "I've got to do that," she resolves. "I'm definitely, umm," Diane continues in characteristic reversal, "giving it a thought."