Liv Ullmann's production of Ingmar Bergman’s “Private Confessions” is at the Kennedy Center Dec. 6-9. (Erik Berg)

Ingmar Bergman was the master of angst, so "celebrate" may be the wrong word for the global 2018 centenary shaping up around the cinema giant's birth. But Liv Ullmann, star of such Bergman cornerstones as "Persona," "Cries and Whispers," "Scenes From a Marriage" and "Autumn Sonata," is thrilled to see so many of the Swedish writer-director's films being adapted for the stage.

“ ‘Autumn Sonata’ is being done as an opera in Finland,” Ullmann says by phone from Key Largo, Fla., where she and her husband, Donald Saunders, share a home when they’re not in Boston or Norway. “ ‘Persona,’ there are performances in China and everywhere. ‘Scenes From a Marriage,’ somewhere it’s two men. His words are so good. He always wanted to be best known as a writer, which he was not. He would have been happy, because the writer Ingmar Bergman will have more of a celebration.”

Ullmann's contribution is a stage version of the film she directed in 1996, "Private Confessions," to be performed by the National Theater of Norway in the Kennedy Center's Eisenhower Theater from Wednesday to Dec. 9. (The Kennedy Center's Bergman tribute continues in April with director Ivo van Hove's "Persona" and "After the Rehearsal.") Bergman's screenplay was based on his mother's infidelity; characteristically, it's a sequence of probing conversations laced with love and guilt, duty and sin as the mother confesses to her uncle, a priest.

The story is drawn from memory and diaries — Bergman’s and his mother’s. After the film came out, Ullmann even got access to letters by Bergman’s father, which now inform the play.

Liv Ullmann was the muse of Swedish writer-director Ingmar Bergman, whose name came to define a genre of movies about the human condition. (Kjerand Nesvik)

"What happened in 'Private Confessions' that Ingmar could never have been witnessing, he's very open about that," says Ullmann, 78, who lived with Bergman for several years in the 1960s (they never married, but they had a daughter together). "He says, 'I wonder what she said?' I have not put myself in as a writer. I think we have to be very careful with biographies and things like this. I can only use his father's letters, his mother's secret diary, Ingmar's diary."

Reversing roles with Bergman by directing, the actress says, “happened almost easily, because I had done some movies. And he was very good. He kept away, didn’t come with advice, didn’t want to see anything until it was finished.” Ullmann recalls arguing over the ending. “I probably cried a little. He actually gave in. Afterward he said, ‘I like what you did.’ ”

She asked Bergman, still vigorous at the time (he died in 2007), why he didn't direct the film himself. "He said, 'I don't believe in God, and you're the only one I know who believes in God.' He even liked it that I put more about God in the film."

True to its title, "Private Confessions" is a sequence of intimate conversations taking place in small interiors and on cozy park benches. The film, shot by longtime Bergman cinematographer Sven Nykvist, is filled with close-ups. Ullmann worried about translating that style to big stages from Norway to the Kennedy Center, where in 2009 she directed Cate Blanchett in "A Streetcar Named Desire" (and where "Private Confessions" will be performed in Norwegian, with projected English titles).

“The stage, sometimes it can be clearer,” she says. “In a film you have the clarity that someone has a wonderful monologue, and you put the camera on that person. Here, there is someone listening who is as important.”

Her roles in Bergman’s pictures could be emotionally lacerating as characters peeled each other down to raw essences. But the hardest, Ullmann says, “was when we lived together. It’s the breakfast when you are angry at each other, and he’s thinking of the movie and I was thinking of him. But what I liked the most with Ingmar was I could phone him after this talk with you, and say, ‘You know what he asked me?’ I miss that.”

If you go

Kennedy Center, 2700 F St. NW. 202-467-4600.

Dates: Wednesday through Dec. 9.

Tickets: $19-$49.