Attending Tea at Five, a one-woman play about Katharine Hepburn now in its world premiere at Hartford Stage, I was reminded of the work’s feisty subject even before the curtain went up. As a disembodied voice issued the standard warning against the taking of photographs, up popped the image of Hepburn, during the Boston tryout of West Side Waltz, striding to the front of the stage to call an audience member who had just snapped a picture " a pig. " That certainly was the most riveting moment of Ernest Thompson’s tepid 1981 work, and it has the dramatic edge on most of Tea at Five as well. But Matthew Lombardo’s play has an irresistible subject, it’s decently crafted, and Star Trek: Voyager star Kate Mulgrew is sensational as the tomboyish Bryn Mawr movie queen, whom she plays in both her Philadelphia Story and her On Golden Pond incarnations.

Set at the ark of a seaside cottage in the Fenwick section of Old Saybrook that was the Connecticut-based Hepburn family’s second home (and to which the film legend, now 94, has retired), Tea at Five presents its subject at ages 31 and 76. In act one, the actress, first dripping from her daily swim, then slinky in a period playsuit and open-toed pumps, has fled to Fenwick after being dubbed " box-office poison " by the Hollywood press. Poisonous or not, she is jockeying by phone for the role of Scarlett O’Hara in Gone with the Wind (The Belle of Amherst notwithstanding, one wonders what one-person-play authors would do without the phone) and contemplating a marriage proposal from Howard Hughes. She doesn’t wed the eccentric tycoon, but the act concludes, as the hurricane of 1938 starts to blow, with the delivery of a package from him, along with a note that reads, " Since your career is in the toilet, I thought I would buy you a plunger. " Enclosed is the script for The Philadelphia Story.

Hughes did indeed buy the rights to The Philadelphia Story for Hepburn, ensuring that if the play proved a hit, the film could not be made without her. Of course, it didn’t happen exactly like this. But Lombardo has done a neat job of shoehorning the events of an entire year — the dismissal from Hollywood, the campaign to play Scarlett, the proposal from Hughes, the family crisis precipitated by brother Dick’s drama-à-clef Sea-Air, and the storm that washed the Hepburn manse right off the beach — into one five-o’clock tea break (de rigueur in the Hepburn house). On this occasion, evidently, the audience is Hepburn’s guest. And when we get invited back again, 45 years later, she picks up where she left off, regaling us with the tale of digging for days to recover the 85 pieces of her mother’s silver buried in the sand by the storm.

Mulgrew’s transformation, however, is impressive. Her head wobbling to indicate Parkinson’s disease, her hair the familiar tangled upsweep of gray curls, this older Hepburn is recovering from a broken ankle; she sports both a walking cast and a cane. And the considerably younger Mulgrew tears into the cranky lioness in winter as convincingly as she personates the silkier, 30ish Hepburn of act one. (Hanging up on Leland Hayward, she purrs in our direction that the caller was " briefly my lover before he became my agent — tragically, he excelled at neither. " ) In both guises, Mulgrew’s re-creation of the sharp Hepburn voice and theatrical mannerisms is uncanny. She even gives us the standard impersonation, the play’s Hepburn witheringly sending up her own disastrous 1933 Broadway outing in The Lake by intoning metallically, " The calla lilies are in bloom again. Such a strange flower. "

The second act of Tea at Five is both more substantive and more awkward. Here the grittier, older Hepburn tells the life-changing tale of discovering, at 14, her adored older brother Tom dangling from a rafter in an aunt’s home in Greenwich Village. And her conflicted feelings toward the father who dominated both her suffragette mother and the rest of the family come out. But surely Lombardo can do better than to use the red sweater Hepburn has tied around her neck to trigger memories of Spencer Tracy. And surely the actor’s unacknowledged love of 26 years can say something more insightful about him than that he was " a marvelous actor and a tortured soul. "

I actually had occasion to visit the Hepburn cottage at Fenwick; I recall it as being more rustic than the parlor created here by Tony Straiges. But respected Broadway vet John Tillinger directs the engaging piece fluidly. And if Tea at Five offers more anecdote than revelation, it has nonetheless a revelation in its star, who almost upstages the star she’s playing. And you thought only Spencer Tracy was allowed to do that.