When the very young Christopher Reeve fainted during a tryout of ``A Matter of Gravity" in New Haven, Katharine Hepburn stepped forward and commanded that the curtain be rung down. Kate Mulgrew exhibits some of the same presence in playing Hepburn in ``Tea at Five" at Hartford Stage. When a mantle collapses as the aged Kate pokes the fire, Mulgrew ad-libs ``Time levels other things as well."

Mulgrew's initially athletic and vibrant, then lame and crack-voiced characterization abounds in spontaneity throughout the world premiere of Matthew Lombardo's play, which opened its already extended run at Hartford Stage Wednesday night.

She animates a surprisingly irreverent play that muckrakes matters that Hepburn and her family would rather forget. Lombardo serves up a spicy ragout that includes a hint of an early abortion, suggestions of dalliances with women and much talk about the well-known affairs with married men: John Ford and, of course, Spencer Tracy.

Lombardo's play is uneven, and its second act feels bumpy, especially when the awkward use of an old red sweater as a polishing rag inspires a long reverie about Tracy (the antique garment was his only bequest to his Kate). The piece is an odd mix of emotionally charged family drama and tidbits of tabloid gossip about the likes of Hepburn's beau Howard Hughes, and often resembles the glimpse of Tallulah Bankhead that Kathleen Turner brought to the Stamford Center for the Arts last season. In both plays, the humor depends largely on catty views of contemporaries, as when Hepburn dismisses the talents of her ex-lover Leland Hayward's wife, Margaret Sullavan. But, in all fairness, Hepburn is equally unsparing with herself, especially regarding her stage work, most damningly in the infamous ``The Lake."

Hartford, Hepburn's childhood home, is mentioned from time to time, with references to the homestead (now vanished) on Hawthorne Street and to Hartford Hospital, where her urologist father practiced and which he aimed, in vain, to head. But ``Tea at Five" takes place at the summer home in Fenwick, the old WASP fiefdom in Old Saybrook, in a disappointingly Yankee spartan space designed by Tony Straiges. Outside, through the magic of Kevin Adams' lighting and some beating rain and faintly falling snow, New England weather plays its dreary part.

Act I takes place in 1938, when Hepburn was campaigning for the role of Scarlett O'Hara but had just been labeled ``box office poison" after a string of flops (which included some of her best pictures, including ``Holiday" and ``Bringing Up Baby"). It ends with the delivery - in a hurricane yet - of the script for Philip Barry's ``The Philadelphia Story," which resurrected her career.

Act II, in 1983, finds a much-changed woman, limping after a recent car wreck, already beset with Parkinson's Disease. A key incident involves Warren Beatty, who is begging Hepburn to return to the screen in what would turn out to be a flop, ``Love Affair."

There is much telephoning in ``Tea at Five," which takes its name from a late-afternoon ceremony that features a precious silver service, dug from the ruins of the Fenwick beach house after the '38 hurricane. Mostly though, when Hepburn is not abusing Hayward, or arguing with her brother Robert, or chatting with Beatty, she expostulates about her career and her men in a rambling, conversational way. In Act II, her reveries are fueled by belts of bourbon, which enhances tea time.

The memories of Spence are pretty much old hat by now. But Hepburn's recollections of the suicide of her beloved brother Tom, in a Greenwich Village attic where Kate found him hanging when she was 14, spark revelations of other relatives who took their lives. In these moments, and in the angry discussions of her domineering father and brilliant but short-circuited mother, ``Tea at Five" takes on some of the darkness of the great family drama of the Connecticut shoreline, Eugene O'Neill's ``Long Day's Journey into Night," whose film version starred Hepburn.

Near the end, the play - directed with unmannered fluidity by John Tillinger - becomes a montage, resembling Alice's pack of cards, with mostly undifferentiated, hasty readings from ``The African Queen" and ``The Lion in Winter," etc., and snatches from her personal life. Here, Mulgrew runs the gamut of emotions from A to B.

Overall, however, Mulgrew gives an impressive account of a still young, deposed queen and a lioness in winter. Her aristocratic bearing, fine features and swept-up hair suit her for Hepburn in her early 30s, and she has the bizarre non-Hartford accent and the intonations nearly perfectly.

Though the second act seems rocky at times, Mulgrew works even more effectively after the intermission, acting the gray-haired, shaking, rasping dowager empress, as Kate bravely contemplates her losses and her family's curse, and peers at a lonely future.