Leave it to Pittsburgh Pops conductor Marvin Hamlisch to put together a sleek and slick musical Valentine.

"The Love Songs of George Gershwin" are the glue holding together this weekend's concerts at Heinz Hall," although the actual representation of that great American composer is surprisingly sparse.

Songs by Gershwin generously share the program with those of Lionel Bart, Irving Berlin, Cole Porter, Michel Legrand and several others, including of course, Hamlisch himself ("The Way We Were," "The Windmills of Your Mind"). And the Gershwin segments are devoted, for the most part, to his most popular pieces.

No surprises here, no unknown gems to be unearthed in this agreeable holiday package.

While more of Gershwin might have been welcome, what is there is smoothly performed by members of the Pittsburgh Symphony, two Broadway-style vocalists, two child singers, and the White Tie Group -- the Symphony's sparkling spin-off jazz combo led by Harold Smoliar (usually the orchestra's English horn player) on piano.

White Tie's imaginative rendition of "My Funny Valentine" on the first half is one of the evening's best moments.

Hamlisch connects the diverse segments with his by-now-familiar homey narratives, telling small anecdotes and occasionally involving audience members -- for example, asking who had been married to each other for how many years. The significant number of couples married for 40 and even 50 years makes for a fuzzy and warm repartee, but it also shows the distinct graying of audiences for events of this kind.

Thursday night's Heinz Hall audience seemed to contain precious few patrons in the under-50 category.

Shortly before the end, Hamlisch provides the best moments when he sits down at the piano, first accompanying orchestra trombonist Peter Sullivan in a virtuoso medley that includes melodies from "Porgy and Bess," then in a solo turn that allowes Hamlisch to shine with his distinctive way of styling "All the Things You Are."

The adult singers are Anwyn Musico, a 21-year-old Canadian soprano with a breezy delivery of her melodies, especially appealing in "Someone to Watch Over Me," and baritone Doug LaBrecque, a veteran of "Phantom of the Opera," among other Broadway hits, whose impressive high extension perhaps calls for the description "bari-tenor." He was at his best Thursday in "Embraceable You" (the second or third rendering of that song during the course of the evening), but he made hay dueling vocally with Musico in Berlin's "Anything You Can Do I Can Do Better."

Middle school students Taia Pandolfi and Brian Brazon demonstrated admirable accuracy of pitch in their unaccompanied vocalizations of Bart's "Where is Love," while the All-Star College Chorus -- an ensemble gathered by Robert Page from 10 or so local colleges and universities -- sang mellifluously a medley that included "Smoke Gets in Your Eyes" and "The Last Time I Saw Paris," eventually joining the entire forces for the closing number: what else, but "Love Is Here to Stay."

Continues at Heinz Hall at 8 tonight and 2:30 p.m. tomorrow. Tickets: $19-$75; pgharts.org or 412-392-4900.