You can still catch Mel Torme's classy act at Charlie's Georgetown, where this musician's musician is blending old Chestnuts and new with a dash of whimsy. He's in fine form: a tad portlier than in his bobbysocks days -- the Royal Air Force blazer could barely contain him -- but light as ever in song.

He breezed through "Lulu's Back in Town," a breathtaking -- but only for his audience -- medley on "New York, New York," a collection of Lena Horne's favorite storm tunes, a clever turnabout on Cole Porter called "You're the Pits!" -- and made it all look easy and, better yet, sound fresh. He also did his own, a torcher called "I'm Gonna Miss You," in which he quoted from his famous "Christmas Song," a.k.a "Chestnuts roasting on an open fire" -- and got the laugh he went for.

An amiable performer, he's open to suggestions. "I'll not only consider requests," he said the other day, "I'll actually do them." He's at Charlie's through the weekend, with two shows Friday, three Saturday and two Sunday. Tickets are $13.50 plus a two-drink minimum; drink prices range from expensive to ridiculous. Call 298- 5985 for reservations.