In A.R. Gurney’s shaggy dog story, “Sylvia,” Tanna Frederick plays a pampered pooch dressed in tutus and tiaras. You might call her a woof in chic clothing.

Frederick, who has starred in four of playwright and filmmaker Henry Jaglom’s romantic comedies (“Hollywood Dreams,” “Irene in Time,” “Queen of the Lot,” and the upcoming “Just 45 Minutes from Broadway”) has clearly found her true métier as a mutt. And I mean that as a compliment, not a putdown. She is a ball of perpetual energy, bouncing on the furniture, assaulting people with frantic affection, rolling around on the floor, and waving her legs in the air as she gets her tummy scratched. I’m sure if she tried, she could wag her tail.

The story of Sylvia is simple, but profound. It chronicles the intense affection that develops between a man and his dog — irrational but all-consuming. She understands him, sympathizes with him, and adores him. So does his wife, but she can’t stand up to this competition. (She calls Sylvia “Saliva” and Sylvia counters with, “He thinks I poo ice cream!”)

Stephen Howard plays Greg, an empty nester bored with his job and looking for a distraction. Cathy Arden plays his wife, Kate, a junior high school teacher enthralled with her work, excited by the freedom that having her kids finally off at college gives her, and thrilled with the opportunity to travel and come and go without restraint. Being responsible for a dog is not her idea of freedom.

Sylvia, a stray who attaches herself to Greg in the park, soon takes over the household. She is everywhere, in constant motion, continually delighting Greg with her adoration and her sardonic remarks. Kate, on the other hand, is not amused. Especially when Sylvia persists in chewing Kate’s shoes.

Frederick is at her best at her doggy extremes: having a hissy fit over a cat in the park, flirting and coupling with her dogfriend Bowser when she goes into heat, and greeting Kate’s friend Phyllis when she comes to visit.

The scene with Phyllis is hilarious. Sylvia, who takes an instant liking to Phyllis, immediately buries her face in Phyllis’ crotch. “Nice crotch,” she murmurs. Phyllis, Tom Ayers in drag, (he also plays Bowser’s macho owner), was taken completely by surprise when Sylvia unexpectedly lifted his skirt and ducked under it to attack his genitals. (This last activity was a sudden ad lib, Frederick revealed in her dressing room after the show.) The pandemonium that followed has to be seen to be believed!

Frederick also revealed that she had designed her own doggy outfits — a wild assortment of more bizarre-than-Barbie costumes and a major indulgence for a woman who grew up loving dogs and dolls.

Award-winning designer Joel Daavid prepared the serviceable set, and since no one is credited with sound design, we must assume that director Gary Imhoff is responsible for the dog-inspired music (“How Much Is That Doggy in the Window?,” “Who Let the Dogs Out?,” et al) that plays during the blackouts. Fun.

Imhoff has directed the play to great effect, although Frederick, who almost never stops twitching and scratching and bouncing around, sometimes becomes as hard to take as a rambunctious two-year old who is continually demanding attention. But the play is called “Sylvia,” after all, and without her constant activity there wouldn’t be too much else going on. Frederick, backed up by three wonderful actors, is definitely the whole show. So, if you love dogs, you’ll definitely want to take her home with you and give her a shoe to chew.

“Sylvia” can be seen Thursday through Saturday at 7:30 p.m. and Sunday at 5 p.m. through July 10 at Edgemar Center for the Arts, 2437 Main St., Santa Monica. Call (310) 392-7327 or visit www.edgemarcenter.org for reservations.

Cynthia Citron can be reached at ccitron@socal.rr.com.