Back to the theater

No, the actress best known for the TV sitcom “Caroline in the City’’ hasn’t fallen off the deep end. It’s a scene from “Caroline in Jersey,’’ a new comedy by Boston-based playwright Melinda Lopez that Thompson is rehearsing at the Williamstown Theatre Festival. The play runs here through Aug. 16.

Chatting with the actress in a rehearsal lounge at the festival, it’s clear that her own picture-perfect life is a far cry from her character’s fast-imploding one. In the play, Caroline’s theater director husband has recently discarded her for an ingenue who’s pregnant with his child. In the real world, Thompson has been happily married to her “Some Kind of Wonderful’’ director Howard Deutch since 1989, and they have two teenage daughters, whom their mother clearly adores. Her character may be on the verge of a nervous breakdown, but Thompson is affable and easygoing, still evincing the same girl-next-door looks and spitfire personality that helped propel her to fame 25 years ago in such films as “Back to the Future, ’’ “All the Right Moves,’’ and “Red Dawn.’’

Despite the differences, Thompson acknowledges that she deeply relates to her character’s midlife career challenges as a woman over a certain age working in an entertainment industry obsessed with youth. (Thompson is 48, but looks at least 10 years younger.) But what she most identifies with is Caroline’s unfailing sense of humor amid the curveballs that are flung her way.

“[Caroline] dips down into real honest sadness and then comes back up with humor. And that’s the way I operate,’’ says Thompson. “In my deepest parts of sadness, I’m always making a joke or being sarcastic. My whole family is like that. And I definitely gravitate toward people who use laughter to pull themselves out of the abyss.’’

In the play, a comedy shot through with streaks of melancholy, Caroline has been forced from the apartment she shared with her husband in Manhattan into a run-down brownstone in the no-man’s land of New Jersey (“It’s like she’s landed on the shores of Illyria - with nothing,’’ says Lopez.) Her career is fading, and to make matters worse, a mysterious figure comes into her life unexpectedly.

The play, says Thompson, is about “how you stand up after you’ve been knocked down - whether you move forward or go backward. And ultimately, she realizes that the best way to pull herself out of the mire is to try to help other people, which is something I find to be very true.’’

Despite the suggestive title (which sounds like a down-at-the-heels sendup of “Caroline in the City’’) and the character of a middle-aged actress, Lopez did not write the play with Thompson in mind. But the casting seems spot-on for this actress, who has a great gift for punch-drunk physical comedy.

“She’s not only funny with her mouth and her brain, she’s funny with her body,’’ Lopez says. “She has this way of being a mess that’s just hysterical.’’

Lopez and director Amanda Charlton were searching for an actress who could nail the physical comedy but also plumb the emotional depths.

“I wanted the audience to really like Caroline and identify with her right from the start. I didn’t want them to think, ‘Oh, this woman is a loser! What’s wrong with her?’ ’’ says Charlton. “And everyone loves Lea Thompson.’’

Although the once-ubiquitous star still works frequently in TV, including playing an ex-secret-agent-turned-housewife in the “Jane Doe’’ movie series on Hallmark Channel, Thompson has seen her film career fade into the background. In the ’90s, she was cast as the single gal New York cartoonist in NBC’s “Caroline in the City,’’ which ran for four seasons. But her decision to focus on raising her two daughters and spend more time with her family may have cost her opportunities in Hollywood.

“It’s actually shocking to me how hard it’s been to get back into the movie business,’’ Thompson laments. “I don’t know why I haven’t done a big feature in about 15 years. That’s kind of crazy.’’

When the film parts didn’t come her way, she instead focused on television and theater. She played Sally Bowles in “Cabaret’’ on Broadway and in the national tour, which led to more stage work.

“I had seen [‘Cabaret’] on Broadway, and I was like, I have to do this. I have to make it happen,’’ she says. “It was a seminal experience. It was hard physically and hard on my family, but there was nothing like it.’’

Performing has always come naturally to Thompson. She got her start as a ballet dancer at the age of 12. She went on to dance for various companies, won a scholarship to the School of American Ballet, and even auditioned for Mikhail Baryshnikov, but eventually chose to focus on acting.

“I’m a big believer in taking the path that’s most clearly presented to you,’’ she says. “Acting seemed like the best way to communicate what I had [inside of me]. I remember in one of the last ballets I did, I played the Snow Queen [in “The Nutcracker’’]. There was this beautiful music, and I just wanted to be free and act the part. But all I could think of was all the technical stuff.’’

Film stardom came quickly. Before long, Thompson was acting opposite such budding young stars as Tom Cruise, Eric Stoltz, and Michael J. Fox, and she was lusted after by teenage boys everywhere.

“Being a movie actress was nothing that I’d ever thought about before. The only dream I had was being in the New York City Ballet,’’ Thompson recalls. “So when my film career took off, I always felt like I was trying to play catch-up because I hadn’t studied acting before. I didn’t know how to manage money or my career. When I look back, I think I was a little bit shell-shocked.’’

Thompson learned about the roller-coaster ride of a Hollywood career early on, when her first monster movie hit, “Back to the Future’’ (1985) was followed less than a year later by one of her most notorious flops, the Razzie Award-winning stinker “Howard the Duck.’’

“I saw the best side of being a star and the worst side of being a star,’’ she says. “And I learned that stardom by itself doesn’t make you happy. If anything, it makes you more insecure and fearful.’’

Today, she has no regrets about her choices. Although she’ll always be thought of as Marty McFly’s time-shifting mom in the “Back to the Future’’ trilogy, she’s still proud of her work in those films.

“From a certain perspective, you could go, ‘Oh, that’s so pathetic. She’s known for a movie she did 25 years ago.’ But what a great part to be remembered for! It was subversive. It was sexy. . . . People don’t remember that they aged me [in the film] to the age I am now. And I got to play all these aspects of this one person, develop her in different ways, and show how one small decision can change your entire life.’’