Sunshine streams through the penthouse windows into the living room -- ricocheting off the lime-green walls, dancing around the baby-blue Lucite tables, kissing the raspberry lamp shades and the outsize wicker couches, which are covered in broad stripes of white, pink and lemon. A graceful branch recently snipped from a cherry tree is apparently convinced that spring is here and is happily blossoming away in a fishbowl vase. The overall effect could be described as Early Lollipop. Or maybe Late Sherbet.

Sandy -- nee Sandra -- Duncan lives here. Did you expect Mata Hari?

With a squeaky clean "Hi, I'm Sandy," she bounces into the room, plops herself onto one of the rainbow couches. For most of America, eight years of upbeat TV commercials for Wheat Thins and 1,000 performances of "Peter Pan" have permanently set her cutie-pie image. This is Shirley Temple the way she was supposed to have grown up; Mary Martin for the 1980s; the Norma Vincent Peale of song and dance, who has built a career on the power of positive vibes.

"Oh, I know what my image is supposed to be. I'm cuuuute, I'm sweeeet, I'm perrrky," she says, extending the adjectives as if she were giving clues on "Password." "That's fine, I guess, if it's part of a larger picture. But I sure don't buy my own act. I see a lot of people who do and they become caricatures. Look, I am going to be 39 next week. No, this week. Tomorrow! Good God! Suddenly, I'm beginning to realize that I'm not getting any answers. I'm not getting any smarter each year about why I'm here. I do wonder, don't you? I just keep plugging along. I put on my little white shirt with the frilly white collar, and find myself asking, 'What is this *%&!*?' "

Last fall, Duncan was seriously considering getting out of show business entirely. She'd just had her second child by her husband, dancer Don Correia, and, as she puts it, "I was out of shape. I'd gained 50 pounds, and I was as big as that chair over there. I was enjoying mothering, the lack of stress and pressure. It was nice to have an excuse not to be out there on a stage. Hell, I've been working since I was 12.

"Maybe it was a bit of a midlife crisis -- being a dancer and realizing how much it takes to get back into shape. An ennui. But there was a lot of cowardice, too. And my husband, rightfully so, said 'You're depressed. I don't think this is the right time for you to make that decision.' "

Instead, she and Correia stepped into "My One and Only," replacing Twiggy and Tommy Tune in the hit Broadway musical that begins previews tomorrow in the Kennedy Center Opera House. Duncan plays Edith Herbert, a 1920s English aquacade star -- "third woman to swim the English Channel, first attractive one," in the words of her Russian impresario -- who falls for a barnstorming American aviator. Not exactly a stretch, she admits, but she does get to sing such Gershwin standards as "How Long Has This Been Going On?" and " 'S Wonderful," and do a tap dance in a shallow pool of water.

"When I first went for costume fittings, the only thing that fit were Twiggy's beaded hats," she laughs. "I kept telling this nice costumer, 'Look, I'll lose all this weight.' I could see her thinking, 'Doesn't every actress who comes through the door say that?' I was kind of scared of doing this show. That sounds silly, I suppose. But Edith Herbert is a pretty lady who wears pretty dresses and stands there and sings, her arms neatly folded. Usually, I have 100 moves on every line. I mean, if I had created the part originally, they'd have had me standing on my head or swinging from the moon. I didn't know if I could please an audience without jumping all over the place. Juliet Prowse and I were talking about this the other night, about how frustrating it is to be getting on and still be expected to kick over your head."

Limiting herself to one meal a day, hitting the dance studio every morning, Duncan pulled herself back into fighting condition, conquered her fear of not flying and won some appreciative notices from the New York critics. It's been smooth sailing ever since.

"Well, I had a death threat a few weeks ago," Duncan says. "First time it ever happened to me. I arrived at the theater and there were all these guys backstage. I thought President Reagan must be there -- or Frank Sinatra -- but when I got ready to leave, they all circled around me and rushed me out to the car. Someone had called to say he was going to kill me that night. It really made me aware of the vulnerability of performers. It shook me for about a week. Every time I'd go down to the edge of the stage, I'd think, 'It would be so easy, wouldn't it!' A lot of people in public life have to deal with that all the time. They have images that provoke it. But me?"

She reflects a moment. "I guess it was somebody who doesn't like cute people. He'd just had it with icky-sweetness." And she lets out a Peter Pan cackle.

Correia has since graduated to the upcoming Broadway version of "Singin' in the Rain," so Duncan will be paired with Tune for the national tour of "My One and Only," which includes a six-week engagement in Japan (where the show will be taped for cable TV). The casting marks a reunion of sorts. When Duncan and Tune were growing up, 30 miles apart in small-town Texas, they often danced together in recitals. "I went back and found a picture of us in my diary," Duncan says. "I was 13 then and very grand, and I wrote, 'This chapter will have to be called The Loves of Sandy Duncan.' It was about these seven guys and I wrote, 'The most peculiar, of course, would be Tommy Tune -- 6 feet 7, a bit arrogant, a bit conceited. But I looove him nonetheless.' My God, all that time he must have been thinking, 'Who is this impossible little 13-year-old girl who keeps dragging around at my heels?' "

She was, apparently, the best dancer within a 100-mile radius of Tyler, Tex., the self-proclaimed rose capital of the world, where her father ran the town's biggest Esso station. At 4, her mother took her to see a dance recital at the American Legion Hall and Duncan instinctively climbed up on the stage. Before long, she was taking ballet lessons every Saturday in Dallas, and at 12 she landed her first part at the State Fair Music Hall, as one of the children in "The King and I." "I was never a cheerleader. I never dated the hot guys. I was never any of that," she says. "I was always outside the circle -- the little ballerina with the bun in the back of her head. My best friend was this girl who looked like a Munchkin. That's why it's so curious for me to have this cheerleader image."

Duncan danced on the local TV station. She danced at Tyler's annual rose festival ("I danced; the rich girls got to be the queens. We had some ugly queens, I'm here to tell you.") She danced for a year at Lon Morris College in Jacksonville, Tex. And by 1965, she'd danced her way right out of town and into a series of musical revivals at New York's City Center.

Her irrepressible energy and her blue-eyed brightness quickly landed her parts in "Your Own Thing," "Canterbury Tales" and "The Boy Friend." She was going to the deli at 4 a.m., hanging out in the Village, living at the Rehearsal Club and leading what, for a small-town girl at least, was the heady city life. Marriage to a fellow cast member of "Your Own Thing" turned out to be a mistake, and in 1971 Duncan was lured to Hollywood. In rapid succession, Disney cast her in "$1,000,000 Duck," Paramount put her into "Star Spangled Girl," CBS gave her her own TV series, "Funny Face." And her saga started turning dark.

"There was all this furor swirling about me," Duncan recalls. "But I was miserable. I felt out of place in California. Its values were not mine. When you're young and cute and all that stuff, you do get exploited by people, particularly in the film industry. There was this strong image of me that was being perpetuated, but it was so distorted. I found myself trying to live up to it all the time, which was driving me crazy.

"Then, as it often happens, I'd get so aggravated at being put in a pigeonhole that I'd react totally opposite. I'd do anything to be shocking. Well, you end up having no idea of your own worth. You become a commodity. I would gravitate toward people who put me down, thinking my own opinion didn't mean a thing. It was all this abnormal behavior."

As the pressure mounted, the headaches began. Then the excruciating pain. Duncan began to crack.

"One night, during the final weeks of the series -- I still had two shows to shoot -- I got up very sick. The doctors didn't know what was wrong with me. They were saying it was my nerves or exhaustion from working until 3 every morning, which it could have been. I was only getting about three hours of sleep a night and I weighed 86 pounds. But this night I was marching in this maze pattern, like I was walking myself into the corner of my mind. I got to the bathroom and suddenly everything went totally white around me, and I said, 'I've lost it.' The panic and anxiety that took a hold of me at that moment were just unbelievable. I saw myself sitting on the end of this big long limb. And then I started fantasizing that I was in an insane asylum and I didn't know it.

"My mother had just flown out that day -- I must have had some residual sense of survival. I'd called her and told her to come out right away. I had certainly never done that before. About 6 that morning, she was going through my phone book, trying to find the name of my doctor. Wouldn't you know it -- that week we were shooting an episode of the show with a doctor, and all I could think of was the name of the doctor in the skit. It kept banging around in my head. Finally, my mother reached my real doctor, and when he arrived, I saw them both, like they were at the far end of a long tunnel. I was sure they were conspiring to kill me."

A team of doctors at UCLA examined her, eventually "took off the top of my head" and discovered a tumor pressing on her optic nerve. Duncan wound up losing the sight in her left eye, although doctors saved the eye itself. "All the time I was in the hospital," Duncan recalls, "all I could think about was how I had to be this good girl and show the nurses how cheerful and strong I was. I never cried. I was Joan of Arc. The positive side of that is that you don't wallow in self-pity. But the down side is that you never admit to yourself how scared you really are. And I was scared to death. I had to go through therapy later to deal with that."

Duncan resumed her series, renamed "The Sandy Duncan Show," the next season, but it was a flop. Disenchanted, she married one of the doctors at UCLA who had first examined her. "He was the opposite of what I'd just been through," she says now. "He represented dignity. He had a valid career, not frivolous show business. We lived in L.A. and we gave a lot of parties for doctors and their wives. I tried to do it right, sublimate myself, be less important than he was. But I was pretending -- pretending to be something I wasn't, pretending I didn't want a career. It pissed me off after a while. I mean, here I was trying to be the good little girl all over again . . . and I'm just not!"

Duncan kept a finger in show business, mostly via TV specials and game shows that wouldn't impinge too deeply on her marriage, and she won an Emmy nomination, playing the nasty Missy Ann in "Roots." But after six years she has characterized as "mildly schizophrenic," the relationship was in trouble. Duncan separated from her husband, put together her own nightclub act and took it on the road. Remembering Correia, "this cute and snappy" dancer from one of her TV specials, she hired him to be her partner. They were married in 1980. For a wedding present, choreographer Ron Field staged a show for the two of them, "Five, Six, Seven, Eight, Dance!" at Radio City Music Hall.

It was, however, her nearly three-year stint in "Peter Pan" that brought Duncan back to the fore and sent her soaring through the show-business stratosphere, albeit on wires. She never missed a performance on Broadway or during an extensive tour. "It would be a step forward in my therapy if I did," she laughs. "That was a real hard show. I would have low back pain -- you know, that thing where you can't even brush your teeth without leaning up against the sink -- and I would finish singing 'Neverland' in a crouch and then have to creak back up into a standing position . . . like Maude Adams. They gave me shots of Xylocaine so I could get on with it, but it was constant abuse to the body."

Two weeks before the "Pan" tour ended, Duncan got pregnant with her first child, Jeffrey. A year later, Michael came along. The children are responsible for much of Duncan's new equanimity. "With two kids, show business just can't be that all-consuming anymore," she says. "I don't think I'm fooling myself. But my happiness -- Don's and my happiness -- just isn't all that tied into the business. Performing is something I enjoy and probably should do, because what else can I do? But it's a job. I train, I've got technique. I'm not striving for the highs anymore and I may not reach a state of brilliance, but that's healthier. My son Jeffrey says, 'Mommy, go do show, kick, dance, earn money.' He's got the idea."

There is talk of another TV series in the offing, but Duncan says she'll agree only if it can be filmed in New York. The old Mary Martin musicals -- "The Sound of Music," "South Pacific" -- keep getting tossed her way, but she sees them as "a dead end." She wouldn't mind a new musical, if it were innovative. "I hate watching most musicals," she says. "They embarrass me. I think, 'Oh, no, now they're going to break into song.' You just can't do that anymore."

Mostly, Duncan has concluded that she wants control over any future projects. "It's the lack of control, I think, that sends you round the bend. Even now, I can't believe that my tumor didn't have something to do with all the pressure, the stress, the confusion. Too much too soon. At the "Night of 100 Stars" the second star-studded benefit held in New York for the Actors Fund , I saw them, the people who care soooo deeply about their careers. There's this desperation about them, this feeling you get that the business defines them. It was fun to be around that many stars and see the ones who can still talk and be human, and those who have been told what they are and can't function on any other level. I mean, the ones who have been told they are dark and mysterious and peculiar act dark, mysterious and peculiar. That wrecks lives. It's pitiful, if you get caught up in it."

Sandy Duncan, who has been told all too often that she's cute as a button and happy as a sunflower, nestles back into a candy-cane cushion, awash in bright sunlight. The furniture dwarfs her, and she looks like a babe in toyland. But the words out of her mouth are, "Frankly, I don't give a rat's ass anymore. Let me learn my lines and do the work. Forget the rest of the crap. I think I've chosen to be a professional."

Her living room is a lie.