In February, 1977, when Diane Lane was 12 years old, she appeared in The Cherry Orchard, directed by Andrei Serban, on LCT’s largest stage, the Vivian Beaumont. “It was a glorious production,” Lane told me this week. “In fact, it was so glorious that it was brought back for a second run later that year.”

This winter, Lane has been back in the building, giving an acclaimed performance, in the Mitzi E. Newhouse, in The Mystery of Love & Sex. “Frequently,” Lane said, “when I enter the stage door, I pass the children who are appearing in The King and I. I feel as if I’m walking past the ghost of my 12-year-old self.”

During the interval between Beaumont and Newhouse, Lane, who grew up in New York and as a child actor toured the world with the La MaMa theater company, worked almost exclusively in movies. From her 1979 screen debut, as a teenager in love with a French boy in the charming A Little Romance, through her films directed by Francis Ford Coppola (The Outsiders, Rumble Fish, The Cotton Club), and on to her Oscar-nominated work in Unfaithful, Lane has lent the big screen luminescence.

“I feel I’ve been book-ending my life with theater,” Lane said. “I gave the middle part to film.” Not that she’s stopped doing movies: later this year, for example, she will appear as the wife of blacklisted screenwriter Dalton Trumbo, in Trumbo.

But for Lane there is a sense that in returning to theater she has restored an aspect of her self and of her talent. That restoration began two years ago, when the director David Cromer persuaded her to play Princess Kosmonopolis, in his production of Tennessee Williams’ Sweet Bird of Youth, at the Goodman Theater, in Chicago. Lane said she had not been onstage since 1990.

Sweet Bird limbered me up,” Lane said. “I never conceived how much effort would be required. I had to dig deep within myself. The play was proof that I could go onstage again.”

With Sweet Bird, Lane was exploring tested material. “Mystery,” she said, “is a brand-new piece. It’s a seed that we are bringing to fruition. I love the freedom of that.” She added: “With Sweet Bird, I felt as if I was jumping off a cliff. This time, I feel much more in my skin. I’m not as frightened.”

Whether she is doing plays or movies, Lane observed that she has “a knack for choosing work that heals me in some way.” With Lucinda, her character in Mystery, she said that there are parallels to her own life. To spell all of them out would spoil some of the play’s plot. It can, however, be mentioned that both Lane and Lucinda have dealt with questions of a mother’s identity once a child has left home. In the play, her twentysomething daughter is Charlotte; in life, Eleanor.

“Dealing with children who have left can be a challenge,” Lane said. “But it’s a wonderful time of life.” She continued: “I always say that I was forced to grow up by being a parent. Kids teach us. Kids raise us. We learn so much about ourselves by learning how to provide them with what they need.”

After speaking eloquently about her character in Mystery, Lane returned to the subject of her own childhood. “When I was in The Cherry Orchard, I think I was a little annoying. I was the pixie dust in that play, not somebody who had to give the big speeches.” She added: “I wasn’t somebody who night after night was engaged in a life-or-death struggle to give a performance. I didn’t realize that one day I’d be the one up there.”

Brendan Lemon is the American theater critic for the Financial Times and the editor of lemonwade.com.