The 1924 George and Ira Gershwin musical "Lady, Be Good" is the sort of unapologetically nonsensical affair where the perennial song and dance man Tommy Tune can just magically materialize in the middle of Acts One and Two and break out into a specialty tap solo. The plot may have stopped for a bit, but it's all good.

While this is not the sort of show you're likely to see revived on Broadway (where old Gershwin properties get reorganized into "new," neatly integrated pieces like "Crazy for You"), it is perfectly at home at the Encores! series at City Center, where it is receiving a gloriously snazzy and merry concert staging.

"Lady, Be Good" arrived on Broadway as American musical comedy was still being developed, breaking out of older traditions such as comic opera and vaudeville while adding youthful energy, a Jazz Age sound and the new dance crazes like the Charleston. It originally starred the brother-and-sister duo Fred and Adele Astaire -- before Fred found a new partner in Ginger.

Its madcap storyline, which revolves around an orphaned brother and sister, involves encounters with various kooky characters (socialite, shady lawyer, gun-toting gangster) and getting involved with get-rich schemes (like impersonating a Mexican widow without knowing a word of Spanish). Toward the end, the brother and sister are doing a yodeling act. Don't ask why.

Of course, it all ends happily. But to get there, we are treated to Gershwin standards like "Fascinating Rhythm" and the title song, plus plenty of other great rarities.

Tune is joined by a vibrant cast of Broadway pros including Danny Gardner (a dead ringer for a young Astaire), Patti Murin, Douglas Sills, Colin Donnell, Jennifer Laura Thompson and Jeff Hiller.

Given that the show's long-lost original orchestrations were meticulously recreated specifically for this production, it would be a crime not to issue a cast recording.

If you go:

3.5 stars

"Lady, Be Good" plays through Sunday at City Center. West 55th St., between Sixth and Seventh aves.,