Brooke Adams, best known for iconic 1970s films like Days of Heaven and Invasion of the Body Snatchers, also has a long stage career on Broadway and in regional theatres. In September she’ll star as Winnie, the oddly sunny, sinking-in-sand protagonist of Beckett’s Happy Days, opposite her husband, actor Tony Shalhoub, who’ll play the small part of Willy, at Theatre @ Boston Court in Pasadena, Calif.

How did you end up doing Happy Days?
The director Andrei Belgrader has been saying to me for years, “I wanna do Happy Days with you.” Every time I would start to read the script, I’d fall asleep. But Andrei is so brilliant, and everyone thinks Beckett is so brilliant, I figured there must be something in it.

Have you changed your mind about the play?
Yes, since I’ve started to memorize it, I fell in love with it; I think it’s fantastic. And then Tony said he would play Willy, which is a tiny part—I didn’t push him at all, he wants to do it.

You and he have worked together a lot, haven’t you?
Well, I don’t really work that much anymore, but I love to work with Tony. It’s how we met, doing The Heidi Chronicles on Broadway. It revives our romance when we work together.

Do you have ideas about what’s going on in Happy Days—why is Winnie sinking into quicksand, for starters?
I have no idea what’s going on—post-apocalyptic something. I don’t think it matters. It’s really a play about relationships and life and death. This woman is so optimistic, it’s unbelievable.

I heard this guy on NPR talking about plants—he was saying they have 7,000 more genes than we do, and the reason is that they’re rooted to the ground and can’t move, so they need to have more sophisticated receptors and take in everything and respond. I’m thinking Winnie’s like that.

Are you optimistic?
Not like her, no. But I guess I am. I have a lot of sort of—natural faith, not having anything to do with God, but with the idea that things will work out. I guess that’s optimism.

It’s a cliché that laymen ask actors: “How do you memorize all those lines?” But with Happy Days, it’s a real question.
I’m getting it, but it’s definitely a great exercise for my brain. It’s all non-sequiturs for an hour and a half, and it has to be done precisely—it’s not like you can improvise around this stuff. But it tells you everything you need to know, and that’s what’s so great about Beckett. Even though he was obviously kind of mad and obsessed about all these little details, he was right; if you do it just like he wants, it works, and it’s funny.

Your father ran a summer theatre in Michigan. Did he encourage you to pursue acting?
It wasn’t so much that my parents encouraged us; it’s that they didn’t really offer us anything else. This is all my sister Lynne and I knew how to do. We would often be woken up in the morning by auditions, by someone belting out Oklahoma! in the next room. We would spend whole summers hunkered down in the theatre. What could be more fun? Neither my sister nor I went to college; we just went right to work.

But you lived in Spain for part of your 20s.
Yeah, that was kind of my college years, ages 20 to 24. I painted. I lived with a Spaniard, and was kind of a housewife for four years. I had been acting before that—did a TV series when I was 16, and I was at the High School of the Performing Arts. I went to Spain to escape everything, to broaden my horizons and see what I really wanted to do. When I came back I really wanted to act.

Are your own kids interested in performing, and do you encourage their interest?
One of our daughters, Josie, is pursuing it; she went to CalArts to study as an actress. I’d just as soon she didn’t want to be one; it can be so heartbreaking if you don’t make it, and how do you know when you haven’t made it? People stay involved in it way beyond the point of it making sense.

Last good book you read?
Me Before You by JoJo Moyes. Also, the Styrons are friends of ours, and I read Alexandra’s book, Reading My Father, which I really enjoyed.

Do you still paint?
Oh, yes. I had a show last November in Santa Monica. I’ve had shows on Martha’s Vineyard. I’m actually thinking about turning our garage into my gallery and showing there.

Do you think of yourself as retired?
Kind of. But I just can’t stop doing projects. I write, I paint, I do a web series with my sister, I decorate.

Wait, what’s the web series about?
We just finished shooting the first season. It’s about two old women, my sister and me. It’s a post-menopausal Girls.