MOUNT VERNON — If you ask Marilyn Pinquoch, the RiverBelle Dinner Theatre has gone to the dogs — and so has she.

Standing on the theater stage during a rehearsal last week, Pinquoch tugged at the pink dog collar buckled around her neck and adjusted her thick ponytails that jutted from the sides of her head like dog’s ears.

All-in-all, Pinquoch closely resembled the little Labradoodle she portrays in the romantic comedy “Sylvia,” which will run July 25 through Sept. 13 at the RiverBelle Dinner Theatre in the Old Town Grainery Building in downtown Mount Vernon.

The little furry home wrecker Sylvia is one of Pinquoch’s all-time favorite roles, one that she’s immersed herself in by taking care of family members’ canines and watching their every move.

As a result, she’s adopted just the right “whine,” the right flirty tilt of the head and that begging position that a dog owner just can’t resist.

But she’s also had to don black knee pads to handle the role’s physical demands.

“I’m all over on the furniture, rolling on the ground, I’m running after a cat that’s under a car,” Pinquoch said with a laugh.

“Sylvia,” written by contemporary American playwright A.R. Gurney specifically for actress Sarah Jessica Parker to play the part of Sylvia, is a romantic comedy of twisted sorts.

Greg, a man suffering through a midlife crisis, finds Sylvia, a little Labradoodle roaming the streets, and falls in love with her.

But Greg’s wife, Kate, isn’t keen on the other female in her husband’s life. The couple’s kids have just gone off to college and Kate has been looking forward to starting a new phase of her marriage with Greg. Gradually, the lovable, sassy little pooch drives a wedge between husband and wife, pushing Kate to great lengths to try to get rid of her husband’s muse.

May sound like some kind of weird lesson on psychology, and in a way, it is, Pinquoch said.

“It’s about relationships, and the stages that people go through in their lives,” she said. “Husbands and wives will identify with it. And anybody who has owned a dog.”

Greg, a pressured financial trader, has been unhappy with his job for some time and looks forward to his outings with Sylvia as an escape. He adores her lack of inhibition and her adventuresome spirit, and desperately wants to imitate her. Eventually, she becomes his obsession.

Amidst the love triangle, a group of colorful characters weave in and out and complicate the plot: Tom, the philosophical dog lover Greg meets while walking Sylvia in the park; Phyllis, an old classmate of Kate’s; and Leslie, an androgynous psychiatrist who bestows marriage counseling on the troubled couple. All are played by actor Tim Brown, who portrayed Professor Plum in the RiverBelle’s early spring production of “Clue the Musical.”

Brown said he’s thrilled by the opportunity to play three very different parts. For one, he has the chance to try out three different accents.

“I think I got the best parts,” Brown said of his over-the-top characters. While the other actors’ parts are more fixed to the script, Brown is able to mold his characters to his vision of how they should move, act and react.

“I get to do whatever I want,” he said, happily.

Beth Greatorex, who portrays the scorned wife Kate, said her toughest challenge has been trying to pretend she hates dogs.

“I love animals,” she wailed.

Whether or not you’re a dog lover, Greatorex said the play is really about human relationships.

“There’s a little something for everyone in this play,” she said.

• Beverly Crichfield can be reached at 360-416-2135 or .