THE REVIVAL of Frederick Lonsdale's enchantingly antiquated trifle "Aren't We All?" at the Kennedy Center Opera House offers the nostalgic spectacle of sly widow Claudette Colbert out to (tastefully) snare perennial ladies' man Rex Harrison.

As it happens, this is the merest subplot to the meringue of a main story, which concerns the harmless infidelities and deceptions of a younger married couple. But no matter -- we're really here to bask in the charm of this venerable duo. Aren't we all?

Written in 1923, Lonsdale's fragile formula farce is an ideal vehicle for Colbert and Harrison, with lots of affectionately joking references to "mummies" and "museums" -- which, of course, they delightfully contradict.

With her dainty beauty and saucy laugh, Colbert's high-spirited entrance in a silver filigree gown sends whispered variations on "Doesn't she look marvelous!" rippling through the audience.

Harrison is urbane and irascible, anything but antique, as he antically wanders the stage looking for opportunities to waggle his eyebrows or wave his feet to give himself and the audience pleasure. They look ever so comfortable together, just sitting and sipping and trading Lonsdale's easy, flirtatious badinage.

With such airy material, director Clifford Williams wisely chooses tradition over camp, and he gets support from a fine cast, who can deliver lines on the order of "I tell you, that kiss meant nothing to me!" with nary an arched eyebrow. Particularly good are Lise Hilboldt as a deacon's starchy wife and Leslie O'Hara as the brazen jazz baby who sets off the marital fireworks.

This is a drawing-room comedy, and Finlay James has constructed two handsomely detailed drawing rooms; Natasha Katz has lit the first in warm lampglow and dappled the second with English country sunlight.