Lithgow talks from the ‘Heart’

“It was a big, important part of our lives. It was the beginning of my storytelling and my enthusiasm for stories,’’ his son, the actor John Lithgow, said the other day, those familiar, plummy tones sounding through the telephone. “And when he was an old, old man and very ill and very depressed, I was taking care of him and my mom for a month, and I hit upon the idea of reading them bedtime stories.’’

It was 2004, and his parents were living in Amherst. One evening, after he’d found the family copy of “Tellers of Tales,’’ he asked them to choose a story for him to read.

“They picked this P.G. Wodehouse story, ‘Uncle Fred Flits By.’ It had been our favorite story when we were kids, but I had pretty much forgotten it,’’ he said. “And I read it to him, and it was like medicine to an ailing old man. It made him laugh, and it brought him back to life.’’

For Lithgow, the pleasure of soothing and amusing his father was accompanied by a frisson of recognition.

“I realized, my God, I’ve stumbled across the best piece of comedy material I’ve seen in years,’’ he said. “All I need to do is memorize this and I can entertain people with it. And that’s what I did. I memorized it and I performed it for some friends, and I told them no more than I’ve just told you, and they loved the story, but what they loved even more is my history with the story.’’

Tomorrow night at the Loeb Drama Center, in a benefit for the American Repertory Theater, Lithgow will perform “Stories by Heart,’’ the solo show that evolved from that moment with his dad. The performance weaves stories from Lithgow’s own life around the Wodehouse tale and a yarn by Ring Lardner called “Haircut.’’

“Ever since I took over the leadership of the ART, I had a plot in my head of getting John to the ART,’’ said Diane Paulus, the theater’s artistic director, who was helped by Lithgow’s habit of returning to Harvard each spring for Arts First, the festival he cofounded in the 1990s when he was on the Harvard Board of Overseers.

“For me,’’ she added, “he’s one of those incredible actors who cross boundaries of theater and film and television, but of course we in the theater always love it when he comes back to the boards.’’

Those Cambridge boards are bound to feel rather familiar. A member of the Harvard class of 1967, Lithgow said he’d been “a very active extracurricular theater wonk at the Loeb,’’ directing, designing, and acting with the Harvard Radcliffe Dramatic Club. Among other parts, he played Gloucester in “King Lear,’’ the title role in “Tartuffe,’’ and King Paramount in Gilbert and Sullivan’s “Utopia, Limited.’’

“So it’s a real serious déjà vu event for me,’’ he said. “As you can imagine.’’

Lithgow developed “Stories by Heart’’ at Lincoln Center Theater in New York in 2008 and ’09 before taking it to the National Theatre in London the following fall. By now he has toured it to cities across the United States. He’s also written a memoir that he said grew directly out of the show. Some of the personal stories cut from the performance due to time constraints are included in the book, “Drama: An Actor’s Education,’’ coming out in September.

In telling the Wodehouse story, from 1935, Lithgow performs all 10 characters in it. In telling the Lardner, from 1925, he mimes the entire thing. “When I was a kid, one of my great heroes was Marcel Marceau,’’ said Lithgow, who is 65. “I saw him quite a few times. I even pulled the curtain for him once.’’ (That was at the McCarter Theatre in Princeton, N.J., where by then Lithgow’s father was the executive director.)

“Uncle Fred Flits By’’ and “Haircut’’ are both comedies: the Wodehouse rather bubbly and terribly British, about the trials endured by Drones Club regular Pongo Twistleton when his country uncle is unleashed upon London; the Lardner sneakingly dark and Midwestern, a story told by a barber who never fails to be amused by antics most anyone else would find disturbing.

“Both stories are about pranksters, very different kinds of pranksters,’’ Lithgow said, then quoted approvingly from a review in The Times of London, which said the tales “buzz with ideas about the pleasures and the price of telling stories.’’

“It makes you think about how there is a sort of latent hostility to a practical joke,’’ Lithgow said. “In fact, there’s an element of cruelty to comedy. And yet, comedy is very funny. We all love it, you know?’’

The winner of two Tony Awards (most recently for “Sweet Smell of Success’’ in 2002) and five Emmy Awards (three for his work on the sitcom “3rd Rock From the Sun’’), Lithgow is also a children’s book author. The impulse to tell stories, and to listen to them, is a matter of some curiosity to him.

“In a sense, I stand onstage and I say, ‘Well, why are we all here? Why do I do this, and why do you come to watch? Let’s think about that.’ But, I mean, it’s not a lecture of any kind,’’ he added, wary that verbalizing the ideas behind the show would make it sound didactic.

“You know,’’ he said, “I’d never written material for myself to perform, at least not material that’s about me and my own life. This is the first time I’d done it. And I think when you get to be over 60 years old, you think a lot about your parents and where you came from and what formed you. The evening is about that, too.’’

Laura Collins-Hughes can be reached at lcollins-hughes@globe.com.