Tyne Daly is certainly no stranger to the New York stage. She has appeared in a plethora of work both on and off Broadway and has collaborated with some of the most pivotal creators of our time, including Terrence McNally and Edward Albee. She also won a Tony for leading the 1989 revival of “Gypsy.”

Now Daly can be found in the Off-Broadway production “Downstairs.” She and her real-life brother, Tim Daly, play siblings with a complicated relationship. Theresa Rebeck wrote the play and Adrienne Campbell-Holt is directing.

Daly, best known as half of the detective team on “Cagney and Lacey,” for which she won four Emmy Awards, can currently be seen in the “Murphy Brown” revival series. Her other screen credits include “A Bread Factory,” “Hello, My Name Is Doris ,” “Judging Amy,” and “Christy.”

We talked to Daly about her role as Irene in “Downstairs,” what it’s like to act alongside her brother, working with Rebeck, and portraying “madwomen in the attic.”

“Downstairs,” a Primary Stages production, is playing at the Cherry Lane Theatre through December 22.

W&H: Can you talk about the evolution of “Downstairs” and how you got involved with this play?

TD: I met Theresa Rebeck up at the Dorset Theatre Festival in Vermont. Tim was doing a play there called “The Scene” and we met afterward. She said, “What are you doing here?” And I told her how much I love to watch my brother on the stage. He had already proposed to her that she write a play for us. I told her that would be wonderful, thinking that we were just making small talk because theater people do that a lot in this business.

But in this case, she did — it was extraordinary. She kept her promise and wrote this play, which is odd enough in this business. I was very impressed because I thought she caught some very interesting stuff in terms of the brother-sister dynamic. In the beginning, I thought this was a play about a brother and sister who save each other’s lives, which is kind of wonderful. But it morphed into a second mounting with deeper echoes about recognizing and defying demons.

The fun part about having a new play, or any play that is a good play, is doing it over and over again. I had a good time with Terrence McNally’s “Master Class” because we did it in three different venues and each time was something deeper.

W&H: How important is it for you to work with female playwrights?

TD: I give to groups that specifically support female playwrights’ work, but I think I’m pretty much an egalitarian about the sex of my playwright. I just want my playwright to be really good. I am not so interested in what their private parts are, just their private thoughts, feelings, and passions.

W&H: What has your collaboration been like with both Theresa and Adrienne Campbell-Holt?

TD: We work well together. We did both in Dorset and here.

Another fun thing about doing a new play is going from the original script to seeing what winds up on the stage. That’s a fascinating part of the process. I specifically wanted to work on new plays when I moved back to New York, which is almost 12 years ago now. I’ve had very good luck with playwrights.

W&H: What’s it like performing with Tim and is this the first time you have worked together?

TD: We are having a hell of a time and I think we’re a good match for this piece. I love watching him on stage, whether I’m on stage with him or sitting in the audience. He’s a good worker. He’s a diligent worker. We run this stuff into the ground every night. We warm up together. He’s a very good colleague.

For me, in terms of the family business, which I’ve now figured out is what I went into and what he went into, I know our parents [actors James Daly and Mary Hope] would be proud of us. I’m an old lady now. Timmy’s an older man. It feels really good to know your parents would encourage what you are doing.

W&H: You act incredibly well together. The scenes where you talk about your mentally ill mother and when you talk about your husband’s control and demons are particularly jarring. Did you do any research into women like her?

TD: All my life. Did you ever read a book called “The Madwoman in the Attic”? That’s a standard of feminist thought about how inconveniently women 150 years ago just got locked up, and their stuff was stolen from them because they were madwomen in the attic. I think that every woman has a madwoman in the attic. What she has downstairs is a whole other subject.

W&H: Do you and Tim compare notes?

TD: We don’t compare stories particularly because part of this play is that each child has a different set of parents. In fact, we haven’t explained to each other what the jokes are they’re laughing about. Irene knows it’s about the raw meatloaf — that is her joke. The second joke we have no idea and I’m not about to find out.

W&H: The stage seems set for moral dysfunction from the start. How does that impact your characters?

TD: The theater’s space is very different to when we were in Dorset. It’s about a third of the size. We had many more steps, it was very, very high. This set feels much more cramped and much more claustrophobic than the first set. So most of our adjustments were to do with space. I have to live in the space and Irene lives in it.

Space reveals itself throughout the play. At the beginning of the play, she spends time in her little corner. When she comes downstairs, her brother has moved in. He’d arrived in the middle of the night. He made a table and he’s got his stuff everywhere. She’s happy to have him there, but she’s already been instructed to get rid of him. It’s double from the top. Then the next long patch is what I call date night. She gets to visit with her brother while her husband is out of the house.

W&H: Then there’s the green coat. I assume it’s symbolic of her freedom in the end.

TD: Irene manages to not be a doormat once her goodness has been offended to the extent that she can’t take it anymore. She’s been protecting and apologizing for a large part of her life. What I liked about the play is not so much getting up and handling it, that part’s easy. It’s being the doormat part. That’s more interesting to play, and women who endlessly defend and apologize for women who are not nice to them.

W&H: What are your hopes with this play?

TD: I know that “Rabbit Hole” and “Mothers and Sons” [other plays Daly has had significant roles in] are plays we started here and are now out there all over the country. If we help it have legs, that would be wonderful.

W&H: I have to mention your bio in the program. It’s very modest, there is no mention of your TV career, but rather that you made your professional debut at the theater in 1966, and “She is delighted to have been invited to play here again.”

TD: I thought, can’t everyone look this stuff up? It was done for a smile really.

W&H: You are filming “Murphy Brown” right now and Tim is shooting “Madam Secretary.” How are you both coordinating your schedules with the demands of this play?

TD: We are actually just done on the set. Last Friday we finished shooting the 13th episode of “Murphy Brown.”

Both companies were very good about bending. We didn’t do the play for the first four or five Fridays so I could film “Murphy Brown,” and we added an extra matinee on those weekends. My dear brother is still doing “Madam Secretary” and will be until the end of our run.