LIV ULLMANN is in a reflective mood.

"I met this girl in Bangladesh," she says, and the soft hush of her voice is like a shawl drawn tight around her shoulders. "It was in a terribly poor village that had just gotten a water pump from UNICEF. To have clean water from a pump had changed the villagers' lives and they were having a big celebration. This girl was in rags, but she was beautiful--I can't tell you how beautiful--and she was holding my hand and dragging me along, wanting to show me something."

Ullmann's blond hair is swept back into a ponytail, accentuating the high forehead, the full lips and the luminescent blue eyes that have focused on an image half a world away. A succession of brooding Ingmar Bergman films and countless women's magazines, not to mention the paparazzi who have dogged her at controversial turns in her career, have made the sensual Nordic features famous. In the sudden stillness that has overtaken her well-appointed Manhattan co-op, they have the gravity of commemorative marble.

"This little girl was talking and smiling and talking all the time," Ullmann continues. "I asked the interpreter what she was saying. I know this sounds made up, but this was how she spoke. She was saying, 'I want to show you all that is beautiful in my life. I want to show you my home and my family. I want to show you everything that grows.'

"Where I come from, a kid does not even want to show you his new toy automobile, because he is tired of it already. But in this poor village in Bangladesh, a child wants to show me 'everything that grows.' I think this sharing is what is meant by joy of life. Everything we believe so important--our possessions, what society thinks of us, what the neighbors say--these are just ghosts."

"Ghosts" is a word that will cross Ullmann's lips often this particular afternoon, even though sunshine is spilling through the open windows, a breeze is lightly ruffling the curtains, and outside summer has put its best foot forward. It is, first of all, the title of the 101-year-old drama by Henrik Ibsen, in which Norway's most celebrated actress will soon be making an American stage appearance, her fifth. (The final production this season in Kennedy Center's CBS-sponsored series, it begins previews Thursday in the Eisenhower Theater. After five weeks here, it will go on to a limited engagement in New York and then tour nationally.) But it is Ibsen's theme--that we are all possessed by worn-out principles, empty conventions and crippling prejudices--that has struck a particularly resonant chord in Ullmann's soul.

In what was once considered one of the theater's most shocking plays, she will be playing what is still considered one of the theater's most challenging roles--the strong-minded Mrs. Alving, who tries to lay to rest the poisonous memories of her philandering husband, only to discover they are alive and thriving in her syphilitic son. Viewed as one of the peaks of the Ibsen repertory, the way Lear and Lady Macbeth are the pinnacles in Shakespeare, the role is traditionally given to an actress in her sixties.

"I was kind of surprised myself when they asked me," admits Ullmann, who wears her 43 years as casually as the olive-drab jeans that are hugging her youthful figure. "But I think it is good for me. A challenge. After all, I could have a son in his early twenties. That doesn't worry me. Being Norwegian, I think I understand a lot about Mrs. Alving."

Ullmann has firsthand knowledge of the sort of narrow-minded Norwegian community her countryman was profiling in "Ghosts." She has experienced the gray Norwegian rain that banishes the sun from Mrs. Alving's sight. She knows the ambivalence of the Norwegian landscape--the high mountains that summon man's purest aspirations and at the same time force him to double back on himself in claustrophobic valleys. One of the triumphs of her career was her performance as Nora, the dutiful wife who, at the end of Ibsen's "A Doll's House," stalks out of a stifling marriage, slamming the door on convention. Ullmann has slammed a few of those doors herself. Like the title of her best-selling autobiography a few years back, she is a fierce partisan of "Changing."

"Ideas," she says, pouncing eagerly on the word, "ideas are the real ghosts of society--the ideas we were brought up with and were expected to conform to. I grew up in a small community in Norway with so many rules about what was right and what was wrong. The religion there is Lutheran and the whole scene is guilt, guilt, guilt. You never get away from it entirely.

"I was expected to be a nice girl, to get married and have children. And I have been divorced. I've lived outside of marriage with others. I had a child without being married. My becoming an actress was even considered such a scandal in my family that a large portion of them never invited me home again. Each time, I got that pang of guilt for not being the nice little girl, for wanting something else. Until recently, I never realized that people actually use guilt as a way to get you to do something. That had never dawned on me before. It has made me a wonderful target for others.

"But on the other hand, I also grew up at a time in society when women were supposed, suddenly, at 17 to be free, to seek what was right for themselves, to try to fulfill themselves. But when I did that, I felt guilty, too, even though I truly believe in the freedom of the individual. Today, it has maybe gone the other way. We're told so much to be free. It's pushed upon us. We have so much choice that in the end it's no choice. We are losing our sense of belonging. People don't believe in family. They don't believe in God. They don't believe in the future. That kind of freedom is also a ghost. It is making us inhuman."

She pauses, silhouetted by a renewed shaft of sunlight pouring in the window.

"Two years ago, I would not have talked like this. Until then, there was nothing else in my life except acting. I went from one job to another. I never had holidays. I knew only the people I met in first-class hotels through my work and whenever I traveled to another country, it was to go on location for a movie. A lot of things I thought I needed then--security, comfort, a career, especially a career--I have found I could do wonderfully without.

"Now I want to act only if it's real, important, if it can say something. I am very comfortable doing a play like 'Ghosts,' but they do not come along so often. Perhaps I am going to regret saying this. I never felt the parts I have acted were critical in my life. Oh, working on them, reading about them, discussing them--that gives you new insight. Shooting a film with Ingmar is like being in good company for a very long time. He makes you feel important about what you do. He demands professionalism.

"At the time, you think 'This is a revelation.' But the revelation is over in a few days and it has changed you very little. The danger is that before long you are wondering if people will come see you. Will they like you? You're thinking all those box-office thoughts that are so foreign to what people are about. No, parts don't change you. Life does. Now when actors talk about their motivations and things like that, I find myself saying, How can I do this? We don't have time to discuss whether or not this character was unhappy in her childhood. There are other things more pressing."

What Ullmann now calls "the most important part of my life" is her volunteer work, as an international spokeswoman for UNICEF and IRC (the International Rescue Committee). For the last two years, she has traveled to the outposts of the planet, observing human wretchedness and--because even in wretchedness there can be nobility--the worth of the human race. Her function, as she has come to see it, is to collect the stories of refugee women and starving children and then relate them as simply and directly as she can at fund-raisers, on television, to the newspapers--wherever money for aid programs can be pried loose.

For the public at large, Liv Ullmann has been one or more of the following: a gifted actress, the woman who bore Ingmar Bergman's daughter out of wedlock, the sometime date of Henry Kissinger and--not all that long ago--the Great Scandinavian Hope of Hollywood. If there was one moment when that changed, it came in February 1980. Along with such notables as Joan Baez, Elie Wiesel, Alexander Ginzburg and Winston Churchill III, Ullmann marched to the border of Cambodia and Thailand, with medical supplies and personnel. The event, organized by the IRC, was calculated to focus international attention on the plight of Cambodian refugees. It also profoundly affected Ullmann, who found herself giving blood for the first time in her life in an army tent in a border camp, while journalists fought to take pictures of her looking wanly courageous.

"Of course, I was aware that there were refugees and hungry people," she says calmly. "But they were numbers. Never did I have the exact feeling that they were my mother, my sister, my grandmother--so enormously close--or that their destiny was so completely out of hand. The woman with a starving child is no different from me. It only happened that war came into her life. I also know now those people have so much to teach us about sharing. That is not dramatic or idealistic. It happens to be the truth. We all are living like outcasts, looking for ourselves. We all want to be touched. I know I do."

The day before the international delegation went to the border, a press conference was held in Bangkok, remembers one of the organizers, Allen Moore, who is also a director of legislation for Sen. John Danforth (R-Mo.). "It was totally disorganized. We were dealing with two languages--French and English. There were representatives of the far right and the far left, who couldn't agree on why we were there. Coming up with a statement was hard. It was hot, humid and dirty. At one point, well into the conference, it was planned that Liv would stand up and make a comment. Her voice was quiet with a quiver in it. Here she was, a world-famous actress, and she talked about herself, as a mother in her forties. No politics at all, just the straight humanitarian, moral concern--the right to live, to eat, to be left alone. The whole place fell silent, and afterwards everyone, including these hard-bitten journalists, broke into wild applause. It was spell-binding."

For the last two years, Ullmann has juggled the demands of her career and motherhood (her daughter Linn is now 16) in order to globe-trot, often on a moment's notice, for UNICEF and IRC. "Travels have exorcised some of my most killing ghosts," she notes. "I know that more and more my happiness has nothing to do with my belongings. In the past, I made some films for the wrong reason--for the money or the excitement--and I know that I cannot afford to do that anymore. My time is not unlimited. Sometimes I think that if everything went beautifully and I could manage, I would love the safety, the warmth, the comradeship of a family. I seem not to have managed that very well, although I have seldom lived alone. And Linn and I--we are a family.

"I also know I am more alive when I am writing. After 'Ghosts,' I have to sit down and try to finish a second book--telling what I've seen and understood in my travels without it being 'Changing No. 2.' I have only the title, which is 'Tides.' If I could make a living out of writing, I think I would do that. I think my life could have more impact if I were not pretending so much as I have in the past."

"Pretending" is what Ullmann has done best--from her days as a resident ingenue, playing Anne Frank in a provincial repertory theater in Sweden, to the intense personal and professional collaboration with Bergman, which resulted in such memorable films as "Cries and Whispers," "Scenes From a Marriage" and "Autumn Sonata." She's even had a fling at a Broadway musical, Richard Rodgers' last show, "I Remember Mama," although even her rare radiance couldn't keep it afloat. Only Hollywood has proved resistant to her special presence, despite a big buildup in the early 1970s that merited her a cover story in Time magazine and such ripe prose as, "Liv: the name rhymes with believe, achieve--or grieve. Also Eve."

"I think they thought that because they had this artsy, Scandinavian actress in Hollywood, they would make artsy movies themselves," she says. "But sometimes it seems that if Hollywood likes what it gets, it doesn't always know how to use it. I had played older women with Ingmar, terribly neurotic and sad. I'm sure they thought, 'We know better. We'll show her young and happy.' And then they come up with the musical remake of 'Lost Horizon'! A total flop. But still they want to groom me to be a star. So next they give me 'Forty Carats,' even though I was 30 and Norwegian and the character was 40 and a New Yorker. After 'Lost Horizons,' half the people at Columbia had to go, it was such a disaster. And then after 'Forty Carats,' the rest of the people in charge left. Really!"

Ullmann is laughing--sunny, girlish laughter. The introspection has lifted. Her face has a white glow, as if bathed in the Northern Lights.

"The next year, I went over to Warner Bros. They knew better. 'She's Scandinavian, Ingrid Bergman, the outdoors type. So they give me a feature called 'Zandy's Bride,' which I quite liked. But I swear to you, when that one opened, half the Warner Bros. studio was fired. Then they said, 'No, she's really Greta Garbo. Give her a queen to play,' and I did Queen Christina in "The Abdication" . That got the rest of the Warner Bros. executives thrown out. In two years, I actually managed to close down two whole studios. I think for a long time after I was on their blacklist. But the reason was theirs, not mine."

It was during her Hollywood heyday that Ullmann also harvested a bumper crop of publicity for her occasional sorties with then-secretary of state Henry Kissinger. When Kissinger slipped away from a state dinner for NATO delegates in Oslo in 1976 to pay her a two-hour visit, reporters clustered outside her appartment and one newspaper speculated in a front-page story on the "Nocturnal Summit."

"I couldn't believe how I was criticized for that," says Ullmann. "My house was going to be burned! Here were journalists all over the world queuing up to get half an hour with this man, and I had this fantastic opportunity to see him, speak with him and everything. Why was my seeing him so different from anyone else? This is a man who has observed so many aspects of the world, and whether his views are your views or not, it's been a wonderful opportunity for me to learn something I otherwise wouldn't."

Ullmann's friendship with Kissinger, she suggests, may well have helped her break out of the tight shell of acting. "At least I had to start thinking about the world so as not to make a fool of myself, although I wasn't supposed to say anything. I was just supposed to keep my ears open. For some reason, Kissinger finds it fun to be with actors and actresses. But I must say, if he was romancing the others as little as he was with me . . . "

She lets the sentence trail off.

"That's part of this world I don't like at all. You are thrown to the media and people make up the most appalling stories about you. Talk about ghosts! The whole publicity machine revolves around someone else. It may be a good you, or it may be a bad you. But it isn't the real you."

The real Liv Ullmann, she lets it be understood, is still in the making.