CAPTION: Pictures 1 and 2, John Denver, and Harry Chapin: by Larry Morris -- The Washington Post

America's National Sunshine Boy, you might call him, or third cousin to a Muppet. The living smile button who sings, relentlessly, about sharing and rushing streams and the incredible miracle of life and love and being just himself, you know, just John Denver.

Then there's Harry Chapin who gets depressed like the rest of us. Really depressed. And who sings, with delicious misery, about diners and Greyhounds and lovers turning up in stale taxicabs.

An unlikely pair. But there they were, both insisting they felt pretty stupid in their visit-to-the-White House clothes, talking up the Presidential Commission on World Hunger. The two are the celebrity contingent on a commission made up of politicians and businessmen, and they were in town yesterday for the commission's first report to Jimmy Carter.

"A tie!" whooped Chapin when he laid eyes on Denver. "Goddamn, I'm impressed."

"Well, s---," answered Denver. "you gotta meet the press."

Chapin, who is normally seen in turtlenecks and a scrunched-up brow, was wearing a three-piece, light blue outfit. "When I'm in Washington, I always wear a suit,' he said, pulling up a sock.

"This may be the third of fourth time in the last several years I've worn a tie," offered Denver.

Here, on the third floor of a drafty townhouse turned commission office on Jackson Place, were two celebrities. One was the gloomy balladeer/ poet known for "Taxi," and the other the cheerful squirrel of "Rocky Mountain High." But both, in their individual ways, had latched on the a cause.

Causes are big in Hollywood these days. They often guarantee good press. And they're good for guilt.

But how to present the cause? Denver and Chapin's reasons -- and approaches -- were as different as they were.

Denver: "I do have faith, and I know I have a purpose in life . . . Because I am who I am, and because I have a large audience out there, it's like I can't pass up the opportunity to speak out."

Chapin: "I busted out of philosophy in college, so don't listen to a thing I say, but it doesn't matter what your motivation is. It doesn't matter if it's liberal guilt."

Denver: "I have no guilt."

Chapin: "I've got guilt. Liberal guilt."

Denver: "The word is not in my vocabulary. I'm a human being and I see other human beings around me."

The implicatin was that he sees them, from behind the owly glasses and blond Dutch-boy haircut, starving. The man who did that for him was Dick Gregory. He's the comedian and also the longest-running protest faster in America who used to jog with Denver, in beefier days, almost 10 years back. On the way to and from those runs, Gregory talked up hunger.

So Denver joined up, first with estfounder Werner Erhard's Hunger Project, then with the commission along with Chapin, who's given hunger concerts for years. On the way, he hitched up with the Cousteau Society, the Wilderness Society, Nuclear Safeguards, New Earth Exposition, the American Indian Heritage . . .

Denver: "I'm not a puppet." He bristled a little at the suggestion that perhaps he's a clebrity mouthpiece for the commission and the other causes. "But," in true Denver fashion, "I'm happy if I am. As long as it's my mouth and the pieces that come out are okay."

Chapin: "It's seen as something corny-out entertainers don't give a damn about."

Denver: "Up until now, survival has depended on, you know, survival of the fittest?"

Chapin: "Yeah, Darwin's theory."

Denver: "If we change that around, we can change the world. See, I believe very strongly that we're put here for each other."

Now he was preaching Chapin held his head in his hand. Denver continued earnestly.

"I mean that 100 percent," he confirmed. "I cannot say it more strongly. The transformation of individual survival has to do with sharing . . . I think all of that reflects the incredible miracle of life."

Chapin: "That may sound like a highfalutin' moral statement, but it's very practical . . . it's very clear cut. A lot of "O" ramifications (and here he made a dollar sign in the air, followed by many circles). The fact is, John Denver could not do a Detroit concert two years ago after he'd done a benefit because he'd used up his Detroit market . . . John doesn't tend to articulate it that way -- he just does it."

Well, there it is. The Sunshine Boy, as gooey as he sings. But somehow, with Chapin apologizing for him, Denver is hard not to like. He seems to mean so well.

Which is maybe why, in a time of cynicism and recession, this American happiness phenomenon just won't go away. Grandmothers love him. Five-year-old adore him.

"I haven't had a hit record in three or four years," he said. "Yet my albums have sold over a million copies. That's phenomenal. There's a large group of people out there who like me -- who relate to me.

"I'll tell you what it is. It's that people see themselves in me. See, you know, it bothers me when I get a bad review. But I don't pay attention to it. I give myself to 20,000 people who are standing up there singing."

Chapin: "He connects to people. He connects. You get it? He connects."