When Joan Allen received the script for Kenneth Lonergan’s “The Waverly Gallery,” she was eager to sign on to the project. It had been some time since her last appearance on Broadway in the 2009 production of “Impressionism” and theater is her first passion. Working with a stacked cast which includes her idol, Elaine May, was another draw. Above all else, it was Allen’s personal connection to the play’s themes that drew her in. Her real-life mother happened to pass away from a similar illness to the one featured in the play just a few years ago.

“The Waverly Gallery” sees the three-time Oscar nominee playing Ellen, the daughter of Gladys (May), an elderly woman with quickly-progressing Alzheimer’s. Directed by the award-winning Lila Neugebauer, the play examines the effect Gladys’ disease has on Ellen and the rest of the family.

Allen’s stage experience is extensive. She first started out as a member of Steppenwolf Theatre in Chicago, appearing alongside her friend, John Malkovich, who personally asked her to join. She later starred in the original production of Wendy Wasserstein’s “The Heidi Chronicles” on Broadway, which earned her a Tony nomination, and in Lanford Wilson’s “Burn This,” which earned her a Tony Award. She has also starred in dozens of films and TV shows, including the “Bourne” franchise, “The Killing,” and “Peggy Sue Got Married.” She received Oscar nods for “The Contender,” “The Crucible,” and “Nixon.”

We talked to Allen about her connection to “The Waverly Gallery,” what it’s like to act opposite May, and the emotional response the show provokes.

“The Waverly Gallery” is playing until January 27 at the Golden Theatre.

W&H: Welcome back to Broadway. How does it feel?

JA: I am loving it. It’s been five years since I last did a play. It was in Chicago at Steppenwolf. It’s feeling really great. It’s a wonderful play that I’m so happy to be a part of.

W&H: What drew you to this particular piece as your return to the NYC stage and had you seen it before?

JA: I had not seen the original production before. They had done it in Williamstown and Off-Broadway in New York, but this was my first introduction to the play.

I thought it was just really beautifully written. My mother had gone through dementia the last couple of years of her life, so I had that first-hand experience with the disease. I thought that really helped me in a way to understand what a family goes through because it affects the entire family enormously. I thought that knowledge was really helpful, and I felt confident that Lila Neugebauer would represent the play very well.

Then there’s getting to perform with one of my idols, Elaine May.

Allen with Lucas Hedges, May, David Cromer, and Michael Cera in “The Waverly Gallery”: Brigitte Lacombe

W&H: That must be incredibly rewarding.

JA: She’s just so incredible, and so honest. I enjoy being on stage with her so much and getting to watch her work. She’s so smart and has incredible instinct and stamina.

Back in my earliest days at Steppenwolf Theatre [she joined in 1977], we would do fundraisers to raise money for Steppenwolf. One of the things we did was go into people’s homes where a board member would have tea or something. We’d try to get material for these and one of the things we did was Nichols and May [the act May had with Mike Nichols] comedy routines. I tried to copy her routines exactly because she was so brilliant. At the time, we had them on a record, and we transcribed and memorized them to perfection. So, I had a history of going way back with her as an actress. It seemed like such a nice connection.

Oddly enough, I’m also friends with [co-star] Lucas Hedges’ father, Peter. We hung out together in our 20s. That was another sign that I was meant to do this play. It’s beauty, working with Elaine, my connection to Lucas. There were just a lot of things pointing in the direction to do this.

W&H: What’s it like stepping into Ellen’s shoes every night, especially given your personal history with the illness the show concentrates on?

JA: I did have a moment when I read this and thought, “I lived this already, do I want to live this on stage eight times a week?” It’s raw, it’s not easy. But these are the things that you are doing in your family. I’m one of four, and we were all taking care of my mother. It was a wonderful situation because she ended up being in assistant living yet we were all very present at different times.

Caregiving is not easy. Ellen is the only child. Caring for her mom has fallen completely in her lap. She has to make all the decisions and take her mother to the doctor, make sure her bills are paid, manage her life. She is trying most of the time to do something. However, I know from experience that it’s not possible to solve the unsolvable problem of the illness. However, you can troubleshoot. Maybe your mother can get a cab from the doctor. That might help. Or cook dinner. Or you can straighten her desk. It’s the little things that you do to try to alleviate a situation you can’t fix.

I empathize with Ellen. I know it’s important to be as optimistic and positive and deal with the situation the best way that you can. I knew there was cream we could put my mother’s hands in. She had to wear Depends at the end of her life, and I was able to go to the store for her. Anything you can do to improve your mother’s quality of life to make it clean and safe, you’re a good soldier. You’re on the ground and you’re figuring things out. That helps you keep from curling into a ball and collapsing.

W&H: What is the response you hear from theatergoers as you leave the theater every night?

JA: It’s just so moving. The sad thing is that the illness is so pervasive. Hopefully, one day there will be a cure. When I come out of the theater, I often hear “I had tears in my eyes because I just went through this” or “I’m ten years into this with my mother.” I also hear from twenty-something-year-old women who tell me they are going through what I’m going through on stage with my mother with their own grandmother and how hard it is. They thank me for helping to tell this story and for raising awareness about the illness. It’s just not talked about a lot so it touches people’s lives to see it represented.