Andy Gibb walks down the aisle of the Concert Hall in the Kennedy Center to find Irene Cara, the rising young singer and dancer in "Fame."

They are as young as the Olympic athletes they are to entertain, but they greet each other with the rites of veteran stars. She gives him a big enthusiastic smile and an embrace, introducing him to people around her. The orchestra is rehearsing, intermittently drowning conversation; crew members scamper to put up the sets and equipment; the Lennon Sisters are practicing.

Both Gibb and Cara, who are to sing a duet version of "Don't Go Breaking My Heart," are barely in their 20s. Yet each is on a different side of the limelight -- she, the actress pushing fast to the top, he the pop star trying to hold his own "stayin alive," as his brothers the Bee Gees would sing.

"Fame. . . I'm gonna live, forever. . ."

Irene Cara belts out the words of the song, in the movie, on the soundtrack album, and now on radios, everywhere as it gets played more and more, as the album sells furiously -- and all the while Irene Cara gets more and more of that elusive, much sought after, much sung over thing called fame.

What she wants now, at 21, is money. "I'm tired of being a poor movie star. I'm going to ask for blood."

She watches the orchestra set up on stage, leans forward in her seat, jumpy with nervous energy. She talks about fame reservedly, even a bit annoyed, crinkling up her face into a patronizingsmile.

"I've been working 16 years, since I was 6 or 7. I was recognized before, I just get more of it now. People always want to make you an "overnight success, but you're not."

She comes off like a veteran who's come up the hard way: Already she's had three agents and credits that include the TV movie "Guyana Tragedy"; the part of Simon Haley's wife on "Roots II"; the movie "Sparkle"; the Broadway musical "Got Tu Go Disco." In August she starts filming a made-for-TV-movie with Jodie Foster about anorexia nervosa in which Cara plays an anorexic.

She even has a stage name. One of the earlier agents changed her last name to Cara. "She did a really nice job. She just took a piece," Cara says, reaching up as if to secton off part of a name hanging in the air, "of my last name."

Her mother is Cuban and her father, a jazz saxophonist who played with Latin bands, is a black Puerto Rican. To pay for her music lessons, her mother worked as a cashier and usher, and her father played music at night and worked in a factory during the day. Cara used whatever earnings she herself made to help pay her way through Lincoln Square Academy, a private school for professional children -- much posher than New York's High School for Performing Arts, whose students are the subject of the movie "Fame."

One reward, she says, smiling broadly, is "getting out of the Bronx." She is temporarily living with her parents in Manhattan's Gramercy Park.

She is tiney, thin -- her manager says she is a size three and always worrying that she is too fat. Her skin is light brown and absolutely flawless. Her long, dark hair, pulled back tightly into a ponytail, has tiny waves in it. Streaks of gray run prominently through it, the only sign that she's not as young as the character she plays in "Fame."

There, she is striking. With her bangs and thick eyebrows, she is Cleopatra-like. "Some people said I look like Donna Summer," she says, rolling her eyes. "You know any black woman with bangs people think looks like Donna Summer."

Cara says the mail pours in from kids asking her how they can become performers. "To tell the truth, I don't answer all of them," she says and grimaces. "Maybe if I had an apartment. I send them a postcard and it says "Thank you for writing, you cansee me in. . . .' But my mother writes them. And she's really the person to do it since she went through it all with me."

Andy Gibb sits in Concert Hall, in jeans and an "I Love New York" T-shirt. "I'm 22 going on 45," he says. "I've been performing since I was 13. Not professionally until I was 16. Not successfully until I was 18."

It shows a bit. He is blond, tan and freckled -- less baby-faced and air-brushed looking than his pictures. His square jaw and a few wrinkles make him look older. He was married at 18 and is now divorced.

Irene Cara can move through the Concert Hall the way she can move through New York -- without too much attention. But for Andy Gibb, there are always autograph seekers.The young fresh-scrubbed boys hold out black-and-white photos of Gibb. "Could you autograph this for my friend? She's got your pictures all over her wall."

Gibb smiles and people standing around chuckle softly. He'd like to keep a certain amount of attention.

"People forget too quickly," says Gibb, now coming back onto the touring circuit after being off it for the last couple of years. "They just don't talk about you much. I see how quiet things can become." He talks easily, affably, optimistically, laughing a bit at himself.

On the road he is usually mobbed, so he takes along six or seven "big Guys" as bodyguards. Not that he's worried for his life. "It just gets a little chaotic. I also carry a pistol and put it next to my bed at night."

A gun?

It's a 357 magnum, he says, "I carry it in a holster, and I never leave it loaded. I just keep the bullets nearby. I've left it in motels before, and I have to call back and say 'Could you send me my gun, please?'" He shakes his head and cradles his face in his hands, laughing.

He laments that he would like to step out of it -- no more just a pretty boy whose fans desperately want him to sing his hit song from two years ago, "Shadow Dancing." He doesn't want to sing it anymore, but he planned to include it in last night's performance.

And he'd like to shed the teenybopper image a bit."People think here's just a good looking guy. There's more music to me," he says. "I'd like to see some adult response to me."

But he's not shedding the clothes that go with it. "I wear sexy-looking clothes because I can get away with it," he says. "I like to be flashy but tasteful. What I'm wearing for the Kennedy Center show has red satin pants."

He lives in Miami Beach near his brother Barry's compound.According to Andy, that's where the Gibbs all kind of hang out together, "dringking cups of tea and writing music."

He wants to sell his house and move to "Malibu Colony," he says. The 58-foot Hatteras yacht is going, too. "I'm selling it to get a bigger one," he giggles.

He's doing a new single called "Time" -- "less soft and lush, more assertive, more upbeat." He's releasing a new album -- "greatest hits." He's doing a movie, which he does not want to discuss. "I'm the male lead," he says.

Gibb stands next to Cara, smiling amiably, looking like another member of the crew. Cara, in her designer jeans and cowboy boots, bounces around excitedly, a little hair comb with strands of beads attached shaking as she turns her head. She grimaces, doubles over, and complains she is ravenous.

She looks up expectantly at Gibb. She takes his hand and they walk away, young and hungry.