You may not know exactly who the actress Harriet Harris is, but I’m willing to bet that she has made you smile — or gasp — in horror. Possibly both. I’ve been bewitched by her since, in an early episode of Six Feet Under, she forced Nate Fisher to lift the coffin lid hiding the mangled body of her late, abusive husband, then laughed hysterically as she realized he could never hurt her again. My jaw hung open again when she cheerfully let her amnesiac husband kill her with multiple insulin shots in order to prove a point in the film Memento. After that, her turn on Desperate Housewives, as a gleefully vengeful sister who cuts off her own finger to help fake her own death, was just icing on the cake. Oh, and she’s a musical comedy diva as well; she nabbed a Tony as Thoroughly Modern Millie’s villainess and nearly upstaged Christine Baranski as Vera Charles in the Kennedy Center’s production of Mame.

Harris touches greatness again in Old Acquaintance, the Roundabout Theatre Company revival of the 1940 John Van Druten comedy of manners. Today the play is probably better known by its 1943 film version of the same name, with Bette Davis and Miriam Hopkins as lifelong friends, both writers, who compete over men, the affections of Miriam’s daughter, and most of all each other’s regard.

Harris stands out in this revival not just because she’s great but because the production around her only occasionally rises to her level. The biggest imbalance is with Harris’ co-star Margaret Colin, who plays Katherine Markham, a serious writer whose books make her a New York literary world celebrity even if — or more likely because — they rarely crack the best-seller lists.

In contrast, Harris plays Mildred Watson Drake, whose books will never win a Pulitzer but which sell ten times as many copies as Katherine’s. She pens trashy, wish-fulfillment beach reads about rich, pretty, glamorous people facing Big Problems that are nevertheless tidily resolved by liberal applications of True Love. The modern equivalent would be Jackie Collins or Sidney Sheldon, without the explicit sex (this is 1940, after all).

Despite reaping beaucoup bucks from this sure-fire formula, Millie is insanely jealous of Kit — emphasis on the insanely. It has always been thus: Harris has a doozy of a first-act speech that she turns into a whirling, breathless aria of long-standing envy dating back to the women’s childhoods. Millie had a nicer house, more money, lots of beaux, but she still felt deprived because Kit was more fascinating, had more fun, and had men interested in her, not silly boys. The rivalry of these two best frenemies continues to this day — the action of the play is essentially a tug-of-war between the women over Millie’s 19-year-old daughter Deirdre (a charming Diane Davis). Deirdre knows her mom’s books are trash, and she regards Kit with admiration bordering on hero (heroine?) worship.