“When I first started, we were going to do full-blown productions of plays, but everybody was working,” noted actress and event co-host JoBeth Williams at the L.A. Theatre Works 40th anniversary gala, held at the Beverly Hilton on Wednesday night. “Then Richard Dreyfuss said, ‘Why don’t we all do radio plays?’ So we’ve been doing radio plays since.”

“This isn’t just a birthday party, it’s a family reunion!” chimed Williams — who’s starred in 20 such plays and will soon be reuniting with Dreyfuss in TBS series “Your Family or Mine” airing April 7 — from the stage. She opened the show alongside L.A. Theatre Works actors and longtime supporters including Hector Elizondo, Judith Light, Susan Sullivan, Edward Asner and Marsha Mason, but the family of actors who’ve given their time to tape these audio theater productions that are broadcast weekly on NPR and heard around the world have also included stars like Hilary Swank, John Lithgow, Annette Bening, Anne Heche, Brad Pitt and George Clooney, who just a few years back, performed “8,” about Proposition 8 and California’s gay marriage laws.

“We started out giving workshops in prisons and, now, we record plays with the most famous actors in the world,” said original founder and current producing director Susan Loewenberg, who wanted to make the theater experience a little less ephemeral and has now amassed a library of over 500 recorded plays — one of the largest anywhere. They’ve also developed an app used in schools, so students can hear Shakespeare performed while reading the esoteric prose. “It’s taking theater and using it to touch all these other aspects of life,” “Castle” star Sullivan said.

“Oddly enough, (L.A.) is not theater central, even though there’s a breadth of talent,” claimed Broadway veteran Steven Weber, who’ll soon appear on FX’s “The Comedians,” and closed the show with a number “in which I tick off dozens of shows that they’ve done to the tune of ‘Doe, A Deer.’” Other pluses to the audio format? “You get a chance to work with great actors, and you don’t have to learn your lines or wear makeup or dress up,” he added.

“It’s a week of your time, you get to be with your friends and colleagues, you get to work on an extraordinary play, a wonderful piece, and it’s very limited in its time frame,” explained Light, who performed “The Diary of Anne Frank” years ago and will start work on “Transparent’s” second season this summer. “So lots of people find that really exciting and interesting and they feel that they can do it and they can work it into their schedule, and it’s fun, it’s great fun.”

“I’m one of the original founders,” said Elizondo, who also recently celebrated another milestone, the 25th anniversary of “Pretty Woman.” (Forget 25 years, “it feels like 25 minutes!” he said, noting it took about six months to get the gang together.) Elizondo is involved in L.A. Theatre Works’ production of an Arthur Miller tribute, is going into the fourth season of “Last Man Standing” and will be doing “another movie for Gary Marshall” this summer. “I only work for friends — and good lunches, and especially for the Los Angeles Theatre Works,” he said.

“Twenty-two years ago I did a show here because of Julia Louis-Dreyfus and her husband Brad Hall, because I had done theater with them in Chicago,” said Tom Virtue, who’s since done twentysomething plays and both national and international tours. Recalling the thrill of working with guys like Kelsey Grammer and John Mahoney when he was just starting out, he added, “This has been one of the best places I’ve ever worked.”

“You rehearse for a whopping two days, and then you bring an audience in for about five performances over at UCLA, and then they cut those together, take the best stuff and then put it on the radio,” spelled out “The Affair’s” Josh Stamberg, who started in the New York theater world and will be starring in a new play opening at the Geffen on April 7 called “The Power of Duff.” “You feel like it’s an oasis, a place where you can get back to doing the thing that you loved, and it feels like getting in the lab with other people that you’ve worked with in the past and you’ve admired.”

Among those he’s admired are Jane Fonda and Stacy Keach, with whom he performed a powerful scene from “Top Secret: The Battle for the Pentagon Papers,” written by the night’s honoree, Geoffrey Cowan. “This is a play that started in a classroom and wound up traveling all over the United States, playing five weeks in New York, and then going to China,” said the USC professor, president of the Annenberg Foundation Trust and first-time playwright, to whom Bill Clinton, Barack Obama and Mayor Eric Garcetti (in person) delivered words of praise. “It celebrates the importance of freedom of the press and an independent judiciary, two great American traditions and institutions,” he said, noting onstage how late Washington Post publisher Katharine Graham “would be turning cartwheels if she knew Jane was playing her.”

Is there much more in store for the accomplished theater company? “Towards the end of his life, Arthur Miller was asked if he had a favorite among his plays,” Loewenberg said at the end of her address. “He gave it some thought and he said, ‘Yes. The next one.’ And I feel the same way.”