Since the 1981-82 season, Franc ois Loup has been recognized by Washington opera lovers as one of the funniest men in town. His slightly angular, larger-than-life gestures have given comic depth to one character after another, and his ability to look proud, shocked, slightly dazed, obsessed or just plain foolish has reduced audiences to helpless spasms of laughter.

Busy laughing, we may not have noticed that Loup's diction and verbal nuances are always right on target, that his voice has a rich, well-rounded tone, his phrasing of musical lines is carefully considered and executed with exemplary control -- in a word, that this outstanding comic actor is also a singer of high quality.

Last night in the Eisenhower Theater, Loup the singer for once got equal billing with Loup the comedian. Both were extraordinary. In his American recital debut, styles ranged from the pure frivolity of two cabaret songs by Offenbach to the pathos and anxiety of Mussorgsky's great "Songs and Dances of Death." With pianist Randolph Mauldin acting as a full partner and searching the music for all its possibilities, Loup performed at the highest artistic level.

Much of the material was comic, from the opening "Ich bin ein Bass" by Edmund Ko tscher to the final encore, Don Magnifico's dream aria from "Cenerentola," and Loup sparkled as he always does when he is given a chance to be funny. In Ludwig Fischer's "Im tiefen Keller," he became progressively more drunk, his gestures grew more expansive, he staggered, he slipped toward the floor, grabbed the piano for support and ended with a resounding hiccup -- all the time negotiating the deep notes of the low-lying melody with perfect precision.

In Ibert's four "Don Quixote" songs, he was the embodiment of chivalric idealism, with an intensely Spanish flavor and finely calculated gravity. The Mussorgsky songs were the highlight of the evening. Between the harrowing "Songs and Dances of Death" and "The Flea" (Mephistopheles' hilarious song from "Faust"), the whole spectrum of Loup's art was sampled.