THEATER REVIEW : Top Hat, White Tie and Tune : Tommy Tune proves to be a lanky heir to Fred Astaire in his appealing if haphazard salute to Broadway at Wilshire Theatre.

June. Moon. Tune.

It’s that last word-- Tune --that does it. That’s the one you want to hang on to in “Tommy Tune Tonite!,” a quasi-solo concert with a supporting cast of dozens at the Wilshire Theatre.

The show’s format may be familiar and its lilting music deja -heard, but as danced and sung by the ineffably elegant, eternally boyish, endlessly tall Tommy of the title, it spells rueful paradox: a celebratory elegy for a Broadway lost, tenderly delivered by one of its few remaining stalwarts.

A nostalgic and romantic evening it turns out to be, but romantic without schmaltz and nostalgic without the sentimentality that often gives nostalgia a bad name. For a virtually uninterrupted hour and 40 minutes, Tune all in white, flanked by dancers Frantz Hall and Robert Fowler all in black, sings, taps, glides, taps, bends, taps, unbends, twirls, schmoozes and, yes, taps again, backed by the anagrammatic TTT orchestra under the exuberant body language of musical director Michael Biagi.

Everyone’s a comedian or what? Actually, yes. Biagi, Tune, the fine Hall and Fowler, and the massive orchestra (too big to be called a band) share the space, the bantering comedy and the music with exemplary accommodation. Once the musicians are in place, there’s just a strip of stage left to dance on. But a strip is enough. It’s not where you move but how .

And so we’re off, into the land of Gershwin, Berlin and Porter, Frank Loesser, Jerry Herman, Peter Allen, even Johnny Mercer and Fred Astaire. If Tune is awed, as he says he is, by Astaire the dancer, he’s also the closest thing to his natural heir, moving with the glissando grace of his predecessor and able, like him, to sing as he dances.

So . . . “Tommy Tune Tonite!” deserves to be seen because how can one pass up a dancer-choreographer of such gigantic talent, proportions and charm? At 5 feet 18 1/2 inches (his description), every last one of which bends like a reed, sways like a willow or collapses on itself like a puppet that has suddenly lost its strings, Tune is an Astaire for the ‘90s.

Were it not for the spell he casts on an audience, one might have had time to notice that the bill itself is haphazardly structured--in fits and starts. Here’s some dancing, then some singing, then some chatting with the public (“Ask me questions”), even a bit of sing-along (“Once in Love With Amy”) and a glowing moment of audience participation when Tune invites volunteers to come dance with him onstage. Nooooooooo problem.

Witty, affable, self-effacing, with a ready repartee and a grin that lights his face up like a Christmas tree, Tune talks easily about cabbages, kings or the tumble he took at Chateau Marmont last May, injuring his foot and forcing postponement of this concert from June to September.

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With his foot on ice--literally and figuratively--Tune promptly joined Barbara Cook in a recording session of which we get to sample the results. The patter isn’t priceless (“The palm trees remind me of my relatives; I’ve always needed someone to look up to”), but it is so seductively dispensed that, well, who cares?

Above all, “Tommy Tune Tonite!” is a concert with dancin’ feet, a modest sound and light show designed to focus on the charms of its lanky protagonist.

It comes with a share of comic oddities, such as “You Go to My Head” performed as a long-legged bossa nova, and the Gershwins’ “ ‘S Wonderful” translated into a distinctly Teutonic “ ‘S Wunderbar.” At Tuesday’s opening, a bashful Tune, his back to the audience, delivered an uncanny spoof of the idiosyncratic Carol Channing. It was a fond tribute to the star who was in attendance.

Mostly, though, “TTT!” is a smooth, undemanding, easy-going event. But it has an arresting episode near the end, when Tune recounts his New York salad days at the since burned-down Variety Arts Building. The 46th Street structure, Tune reminds us, was home to the creativity of Bob Fosse, Gower Champion and Michael Bennett. The memory of their loss segues naturally into a listing of Broadway artists lost to AIDS.

This is a shattering moment, not only in its emotional intensity, but as a sobering reminder that Tune, Graciela Daniele and Susan Stroman are the only choreographers of stature left on Broadway.

Somehow, the following number, which closes the show (Al Dubin and Harry Warren’s “Shanghai Lil”), is out of step with the mood of that moment. Almost anything else might have served better to lift our sagging spirits--something less frivolous, less disconnected, more keyed into the memory invoked.

It’s a small complaint. We forgive it with this show’s other transgressions, because Tommy Tune is what we’re there to see and he’s very much all there, start to finish: Mr. Music-in-Motion, an unlikely angel in top hat, white tie, tails and tap shoes, all 78 1/2 inches of him floating above a strip of dance floor he never seems to touch.

* “Tommy Tune Tonite!,” Wilshire Theatre, 8440 Wilshire Blvd., Beverly Hills. Tonight-Saturday, 8 p.m.; Sunday, 7 p.m.; Saturday-Sunday, 2 p.m. Ends Sunday. $18-$37.50; (213) 480-3232. Running time: 1 hour, 40 minutes.