One does not expect preeminent actors performing dramatic scenes at a party.

Yet that’s exactly what took place during “Every Act of Life,” an Austin weekend of festive events dedicated to playwright Terrence McNally.

The occasion for the jubilee was the one-time Texan’s 80th birthday. McNally has lived in New York since the 1950s, but he is drawn back to Texas and, specifically, Austin, where his archives are preserved at the Ransom Center on the University of Texas campus; where he and his husband, Tom Kirdahy, a theatrical producer, have made lasting friendships; and where our top resident company, Zach Theatre, has produced more plays in the past decades by McNally than any other writer.

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Zach artistic director Dave Steakley announced that unlooked-for fact at a brilliant dinner party in the Rob Roy-area home of philanthropists and Broadway producers Marc and Carolyn Seriff on Saturday. Seldom have I witnessed so many guests, perhaps 100, come together so fully over the course of an evening for such a happy occasion.

Sunday, the Ransom Center hosted a screening of the biographical documentary, “Every Act of Life,” at a campus theater. Directed by Jeff Kaufman, it is already available on iTunes and video-on-demand services.

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Among the things I learned when I streamed it: Edward Albee was McNally’s first partner; his first Broadway play was a huge flop, but he got right back up on the horse, as encouraged by John Steinbeck; Angela Lansbury was the angel who gently convinced McNally, who came from a heavy-drinking family, to give up alcohol; and the playwright has been enormously influential in the careers of dozens of actors and writers.

Among the luminaries who appear in the film are F. Murray Abraham, Christine Baranski, John Glover, John Kander, Lynn Ahrens, Larry Kramer, Nathan Lane, Joe Mantello, Audra McDonald, Rita Moreno, Chita Rivera, Doris Roberts and Richard Thomas.

Some of those stars appeared in the flesh at Zach’s Topfer Theatre on Monday night, along with the cream of Austin stage talent. We heard McNally’s off-stage words, but also long, loving scenes from his plays, such as “Love! Valour! Compassion!” “Frankie and Johnny in the Clair de Lune,” and “The Lisbon Traviata,” plus the paired dramas with gay and AIDS themes, “Andre’s Mother” and “Mothers and Sons,” which added Michael Learned to the acting mix.

It was gratifying to see alongside acting greats like Thomas, Learned and Glover, as well as Ben Hunlan, who appeared in “Once” at Zach, equally compelling Austinites such as Babs George, André Martin, Martin Burke, Lauren Lane and David R. Jarrott.

Chita Rivera dazzled the crowd with her presence, even though she had a “froggy” voice and couldn’t sing a number from “Kiss of the Spider Woman.” In great voice was Christy Altomare, down from Broadway for the night to sing key songs from “Anastasia” and “Ragtime.” McNally wrote the stories for these and many other musicals and operas.

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As a very last gift to McNally, Jill Blackwood and Mel Maghuyop reprised scenes from “The King and I,” the very first musical that the young McNally saw on Broadway.

All this activity anticipates the arrival of a McNally regional premiere at Zach in June and July, “Fire and Air,” based on the history of the Ballets Russes and the relationship between impresario Sergei Diaghilev and dancer Vaslav Nijinsky.

Monday morning, I was extremely privileged to interview McNally for 40 minutes at the Driskill Hotel. Expect a larger story based on our chat to run in time for the opening of “Fire and Air” in 2019.