It is hard to imagine "Thank Heaven for Little Girls" being sung properly by anyone but the ultimate dirty old man, Maurice Chevalier, but the National Symphony Orchestra's pops conductor, Marvin Hamlisch, found a new approach in yesterday's program.

 
The thematic number from "Gigi" was sung by Rocky Paterra, an 11-year-old showbiz veteran from Pennsylvania, while four little girls, all dressed in hyper-cute frocks, came onstage one by one and tried to win his exclusive attention. But it was not meant to be; a fifth little girl was dressed for a baseball game, with slacks, jersey, glove and cap, and Paterra walked off with her while the others walked off indignantly.

There are always a few surprises in Hamlisch's programs; the other big one yesterday was in the last number on the program, "Get Me to the Church on Time."

As the orchestra struck up the introduction, a patron sitting quietly in an aisle seat got up and staggered drunkenly to the stage, accosting several patrons on the way, then hoisted himself laboriously onto the stage and gave a show-stopping performance of that boisterous number (also, come to think of it, an anthem for a dirty old man). All the other soloists (soprano Teri Hansen, tenor J. Mark McVey and baritone Brad Little) were from out of town, with careers centered on Broadway. But Mr. Doolittle's "My Fair Lady" number was sung by John Leslie Wolfe from Bowie -- a performer of extraordinary talent, if we can judge by this one song.

The others all gave first-class performances in a program devoted to the musicals of Lerner and Loewe, although they took a few minutes to reach their peak form, perhaps because of post-Thanksgiving lethargy.

After a couple of numbers from "Brigadoon," Little and Hansen scored a duet hit with "Almost Like Being in Love," and McVey followed up immediately with a smashing performance of "I'll Go Home With Bonnie Jean."

The second half was devoted to music from "My Fair Lady," with the spotlight on Hansen, who shone in "Wouldn't It Be Loverly," "The Rain in Spain" and "I Could Have Danced All Night."

McVey's voice was exactly right for "On the Street Where You Live." The orchestra and chorus (Washington Men's Camerata and Washington Women's Chorus) were excellent throughout.

There will be a repeat performance tonight.