Produced by the Dorset Theatre Festival. At Dorset Playhouse, Dorset, Vt., through July 8. Tickets $39-$52, 802-867-2223, www.dorset

After decades of working in show business and on television, actors Tim and Tyne Daly still marvel at the surprised reactions they get when longtime fans find out that they’re related.

“We’re still stunned and shocked that a lot of people don’t know that we’re brother and sister,’’ says Tim Daly, 61. who plays the theologian-turned-NSA operative husband of Tea Leoni’s secretary of state on CBS’s “Madam Secretary.’’

Blame it on their 10-year age difference, perhaps.

“Yeah, occasionally people say to me, ‘Gee, I love your son.’ And of course that is just annoying to me,’’ says the 71-year-old Tyne, in that brassy voice known to longtime fans of the pioneering ’80s female detective series “Cagney & Lacey,’’ for which she won four of her six Emmy Awards.

Despite the Dalys starry television profiles and diverse theatrical resumes, they have never performed onstage together professionally — until now. The brother and sister duo, who grew up in a show business family, are teaming up to headline the world premiere of Theresa Rebeck’s “Downstairs’’ at the Dorset Theatre Festival in Dorset, Vt., through July 8. And they’ll be playing brother and sister, to boot.

“Downstairs’’ began as something of a mutual dare between the Dalys and Rebeck (“Dead Accounts,’’ “Seminar,’’ “Mauritius’’) a few years back. Tim, who spends his summers in Vermont on a farm he owns near Dorset, had played an out-of-work actor whose life spirals out of control in Rebeck’s play “The Scene,’’ which was produced at the festival in 2013.

After that run concluded, Rebeck told Tim they should work together again, and he suggested an irresistible idea: “Why don’t you write us a play for my sister and I?’’ he recalls telling Rebeck. “And Theresa said, ‘Don’t say that unless you mean it.’ I thought there was no possible way she’s ever going to do that. She’s just going to blow me off.’’

But a year later, he found himself holding a stack of papers that represented a play Rebeck wrote for him and Tyne.

“She kept her word, and this seemed like a rare opportunity to work together,’’ Tim says. “Now here we are actually doing it.’’

“You would be crazy not to take that invitation seriously,’’ says Rebeck, over the phone from her summer home near Dorset. “I wrote the play with them in my head, and then weirdly there were details in it that were spookily accurate about their past. Then we spoke some more, and other details from all of our lives started to inform the writing of the play. There were aspects of their childhood that drifted through the ether of my subconscious into the play itself.’’

In “Downstairs,’’ Tim plays the eccentric, paranoid Teddy to Tyne’s troubled Irene. With Teddy’s mental state beginning to fray, the character winds up moving, uninvited, into the junk-filled basement of his sister’s house, much to the exasperation of her controlling husband Gerry (John Procaccino). Insisting that he needs to stay there temporarily, Teddy expresses fears that he was poisoned at his job and insists that he’s found something nefarious on her husband’s old computer. Irene believes her brother is on the verge of a breakdown. But before long, the tables get turned and he’s questioning Irene’s own illusions about her less-than-ideal domestic life.

“They love each other and they scare each other, and they worry about each other,’’ Tyne says.

“They’re contentious, and they drive each other crazy and hurt each other,’’ Tim adds. “They are very much like siblings. But they do look out for each other.’’

“They talk over each other, too,’’ adds Tyne, with a laugh.

Tim says he appreciated that Rebeck wrote a role for him that ran counter to the previous parts he’s played, including obsessive-compulsive airline pilot Joe Hackett on “Wings,’’ alternative medicine doctor Pete Wilder on “Private Practice,’’ and drug-addled screenwriter J.T. Dolan on “The Sopranos.’’

“I was immediately drawn to Teddy. Any damage that I have, Theresa sees it, and she likes to weave that into the play. Most of the time in the commercial acting world, I tend to play organized people. But Theresa somehow sees underneath that to the chaos. So I get a chance with this play to illuminate that part of me through the character of Teddy.’’

Says Rebeck, “I realize that my subconscious seems to have landed on an aspect of Tim that’s very cerebral and passionate. He’s that insanely good-looking guy who’s seen as this straight-up heroic figure in many of the things he gets hired to do, and that’s not what this is at all.’’

Tyne, too, felt like Irene went against the grain of the characters in her usual wheelhouse.

“I like to think I haven’t been typecast as an actress,’’ she says. “But this is a special opportunity to play the kind of character I’m not always hired to play’’ — more subdued and reserved than the irrepressible, self-assured, brassy broads she’s often portrayed, including working-class gumshoe Mary Beth Lacey on “Cagney & Lacey,’’ no-nonsense social worker Maxine Gray on “Judging Amy,’’ and the indomitable Mama Rose from her 1989-90 Broadway turn in “Gypsy,’’ for which she won a Tony.

“Irene is very mild. She has trouble standing up for herself. She’s tried to stick to a life that’s very unsatisfying. Then her brother comes, and they haven’t seen each other for a long time, and in the course of the visit she learns a lot about how to be a grown-up.’’

Tim and Tyne also hope that their real-life relationship feeds into the complex dynamic between their onstage characters. “Since Tyne and I are actual brother and sister,’’ Tim says, “it is our hope that there’s a palpable chemistry that will be felt by the audience because we do have a real history together and we do have shared memories.’’

The production is also bringing back a flood of childhood theatrical memories for the siblings. Their father James Daly was an Emmy-winning television actor who starred for seven seasons on the 1970s series “Medical Center,’’ and their mother Hope Newell was a respected stage actress.

“Both of us have a nostalgic place in our heart for summer theater,’’ Tyne says, “because our parents did summer stock through all of our childhoods.’’

She vividly remembers going with her two sisters to the theater and the excitement building as the lights went down. “Then some people would come out onstage that looked a little bit like my parents. But they were onstage with different accents and different looks. I just thought that was the most fantastic magic trick — that they could morph into these new people and then afterwards morph back into my parents again.’’

Watching his father do summer stock, Tim says, was when he first “fell in love with the theater as a concept. It was our temple, our place of worship. And here we are decades and decades later doing it ourselves.’’


Produced by the Dorset Theatre Festival. At Dorset Playhouse, Dorset, Vt., through July 8. Tickets: $39-$52, 802-867-2223,

Christopher Wallenberg can be reached at chriswallenberg