The "Merry Widow" will be 79 years old next month, but she retains a sparkling personality, a compelling charm and a remarkable energy. Certainly, she is frivolous, and her morals may be no better than they need to be, but there are those who love her -- thousands of them in Washington alone.

Last night, when "The Merry Widow" appeared at the Kennedy Center, under the auspices of the Washington Opera, that love was fully justified, fully satisfied. The grand old lady has never looked or sounded better.

For this lavish new production, starring Mary Jane Johnson in the title role, the Washington Opera has gone all-out. The applause began last night in the Opera House before anyone had sung a note -- a well-deserved tribute to Zack Brown's magnificent Art Nouveau set and lavish costumes. But enthusiasm quickly grew to encompass every aspect of the production: Cal Stewart Kellogg's conducting, Baayork Lee's choreography and Peter Mark Schifter's stage direction.

Above all, this production has singing of consistently high quality from performers who look their parts and know how to act as well as sing. This is a beautifully balanced and integrated performance, with all its parts working harmoniously together for maximum impact.

It is sung in English, a tactic that does not always work well in the Opera House (witness Bernstein's "A Quiet Place" and the Metropolitan Opera's "Mahagonny" and "Peter Grimes"). But for this production, the diction is precise and the projection strong and clear -- even (most of the time) from the sopranos, the voices that usually suffer (or cause) the most problems with clarity.

Much of it is spoken, of course, and Schifter has directed considerable attention to such matters as stage business, the physical disposition and movement of soloists and chorus, particularly to the timing of lines. When Danilo, the unrepentant roue', asks, "I, apologize?" and Hannah, the merry widow says, "Accepted," the timing is as precise as if they were singing and following a conductor, and the laughter is consequently heightened. This production looks as though it could work as a spoken play without any music.

But, of course, the music is the main attraction -- as sparkling a collection of good tunes as you will ever hear this side of "Die Fledermaus." Kellogg captures all of its sparkle, aided by an orchestra that sounds in unusually good form, a bright, vigorous chorus and excellently chosen principal singers.

Johnson is both earthy and polished in the title role -- like a peasant girl who has suddenly become a rich widow. She had occasional small problems of projection, but they were minimal and her voice was rich and accurate, her interpretation stylish.

Richard Stilwell perfectly portrays Danilo Danilovitch: cynical, dissipated, bitterly witty and driven to heights of romantic absurdity by his quixotic sense of honor. His voice is probably the best in the production, and his stage presence is commanding and convincing -- as a comedian and a romantic lead. With anyone less compelling than Johnson in the title role, he would dominate this "Merry Widow."

Wendy White is totally charming as Valencienne, who remains "a virtuous wife/enjoying my station in life," almost against her will. And David Kuebler is suave and debonair as Camille de Rosillon, the Parisian ne'er-do-well who ardently tries to lure her into an affair. All four were in fine voice last night, though Kuebler took a bit longer than the others to get there.

A lot of the production's impact can be attributed to the expert casting of secondary roles. Donald Adams, a veteran of the D'Oyly Carte Company, strikes exactly the right tone of pig-headed pompousness in the role of Baron Zeta, the ambassador. Zale Kessler (Njegus), whose credits include a lot of work on Broadway, television and spoken theater as well as opera, seems more an expert comic actor than a singer for most of the performance. But at the beginning of Act 3 he steals the show musically for a few minutes with a song-and-dance number, "Tre s Parisien," leading a chorus of six dancers with top hats and canes. I do not recall this number from dozens of previous "Merry Widows," and some of its rhymes are outrageous ("I have learned which vine one serves/ with a plate of hot hors d'oeuvres."), but it doesn't matter; in this performance, it works beautifully. Christopher King, a local tenor who was given a small role in last year's "La Belle He'le ne" gets a slightly larger one in this year's "Merry Widow" and sings it well.

The dancers, in a variety of roles that range from Pontevedrian peasant folk dancers to chorus girls from Maxim's, perform stylishly and energetically. Some of the choreographic ideas are quite striking -- for example, in the Maxim's scene, in which the chorus girls dive one after another from a high railing into the outstretched arms of a group of male choristers, from which they somersault to the floor. Elsewhere, they are elegant as partygoers at an embassy ball, and earthy in the folk dance that opens Act 2.

The sets are magnificent -- no smaller word will do -- with Art Nouveau motifs worked into all kinds of corners: the elaborate elevator serving the central staircase in Act 1, the stained-glass gazebo (crucial to the plot) in Act 2, even lighting fixtures and the proscenium of the stage-within-a-stage for the Maxim's scene in Act 3. Visually -- and in many other ways -- this is the most memorable "Merry Widow" I have seen. John McLain's lighting, always excellent, is particularly striking in Act 2 of this production: the widow's garden party, with day gradually fading into night, shadows deepening and stars coming out.

The text used is the fine English adaptation by Ted and Deena Puffer, and in many ways it equals or even improves on the original. The spoken dialogue is, of course, fair game in any production of this work. This time, it is tightened to make it faster-moving and more dramatic; some traditional one-liners are dropped without any perceptible loss in comic effect. A bit of music is also added from another Leha'r operetta and it fits in easily.

The most significant change, perhaps, is the "Dummer, Dummer Reitersmann" ("Silly, Silly Cavalier") duet, which is transferred from Act 2 to Act 1, with the words changed so that it becomes a direct exchange of insults between the Count and the Widow, advancing the plot and sharpening the character portrayal.

Applause was long and hearty at the end, and the opera company joined in the tumult, sending a cascade of red balloons tumbling from the ceiling of the Opera House into the audience. Little touches like this, like the flower-decked swing in which the widow begins her "Vilja" song, the Pontevedrian flags and uniforms, and particularly the hilarious national salute (ending in "Hup, Hup, Hup") add greatly to the charm of a highly enjoyable evening.