I first saw Patti LuPone, currently starring as the community-theater maven Irene in Shows for Days, onstage in Three Sisters. It was 1975, I was in high school, and the world was free of cellphones. LuPone was playing the youngest sister, Irina. The friend with whom I went insists to this day that the production, from The Acting Company, also featured Kevin Kline. It did not. Kline had played Vershinin when the Chekhov production was on Broadway in 1973-74, but had moved on by the time of the reprise, in repertory at the Harkness Theatre.

Of LuPone what I chiefly remember is the passion with which Irina insisted she was a grown-up. I also remember thinking that I wished I had seen her, as Lady Teazle, in The Acting Company’s earlier production of The School for Scandal. It had been presented, in 1972, at the Good Shepherd-Faith Presbyterian Church, which is on West 66th street and shares a city block with the Juilliard School, from which LuPone and Kline had graduated in the famous first class of the Drama Division.

It would be a decade and a half before LuPone would cross the street from Juilliard in the other direction and star in Lincoln Center Theater’s production of Anything Goes. The association blossomed: LuPone married her husband, Matthew Johnston, on the stage of the Vivian Beaumont, where the Cole Porter show was playing.

In 2000, she returned to the Beaumont twice weekly to perform the concert Matters of the Heart. It was conceived and directed by LuPone’s longtime pal Scott Wittman, who had been the one, seven years earlier, who had introduced me to LuPone in London, where she was starring in the musical Sunset Boulevard. We all went out for drinks after the performance, and I marveled that a woman who had that day done two exhausting shows could still exhibit such gusto into the wee hours.

I was not surprised to find LuPone indomitable – her hard-working reputation had prepared me for that. I was, however, a little surprised to witness her sensitive side. Performers who have diva-dom in their blood (LuPone’s great-great aunt was the 19th-century opera singer Adelina Patti, whom Verdi called “a stupendous artist”) are thought to be tough and unsentimental when, in fact, they are just as likely to be poetic and misunderstood. Anyone who witnesses LuPone’s backstage manner, where I have numerous times heard her offer encouragement to young actors she passes in the hallway, cannot long believe all the stories carrying negative connotations of the d-word.

As for that reputation, she dissects it better than anyone in her 2010 book, Patti LuPone: A Memoir. (I still think that volume, echoing her Tony-winning turns in Evita and Gypsy, should have carried the title suggested by a fan: “Don’t Cry For Me – For Me! For Me!”) She confessed how she misbehaved with David Mamet in Palm Beach, heaved a lamp out a second-floor window of her Sunset Boulevardtheatre in London, and cried in front of Arthur Laurents before the opening night of Gypsy on Broadway. LuPone also revealed that John Houseman, who ran Juilliard’s Drama Division when she was there, once “grabbed me by the throat, started shaking me furiously and said, ‘I want to beat you black and blue until you are bloody with bandages all over your face.’” (He hadn’t been able to understand what she was saying during a crying scene.)

The crying scene was in Three Sisters. I lied at the beginning of this blog entry when I said I saw LuPone in that play on Broadway. Or, rather, I did see her, but only the second act. In those long-ago, non-digital days, it was possible to “second-act” a show – sneak into a theater at intermission, find an empty seat, and enjoy the final half of something for free.

This practice has more or less vanished. House staff at the entrance now tend to ask to see a ticket stub as you re-enter.  While I can understand this enforcement in the interest of fairness and security, I lament the change on behalf of poor students. In Shows for Days, Michael Urie plays just this type of teenager, the kind I also was in the 1970s– newly smitten with theater and aching to expand his experience of it. I suspect that these days he could only crash a show in the company of someone as hard-charging as LuPone’s Irene. That character’s name, by the way, comes from a Greek word meaning “peace.” This is what we call irony.

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