The 23-year-old Chinese pianist Lang Lang will perform at Carnegie Hall tonight. To be sure, the audience will hear unmistakable talent coming from the stage. What’s unclear is what the audience will see.

In September, Mr. Lang’s performance with the New York Philharmonic was broadcast via the PBS show “Live From Lincoln Center.” The audience at home was treated to a display of ebullient character that those in Avery Fisher Hall largely missed. Mr. Lang sometimes plays with eyes closed, head tilted back, but this time, his eyes were wide open and, as often as not, trained on the television cameras. His overly enthusiastic movement went even beyond his usual stage movements; he has a tendency to conduct with a free hand or glance at those in nearby seats as if to enlist their support in tackling a tough piece. But viewers witnessed a brazen experiment.

Of course, no musician is expected to sit solemnly still. The late Jacqueline du Pre bobbed and weaved through her performances. But her whole being radiated a musicality that no one who saw her perform can forget. By contrast, Mr. Lang’s beaming smiles to the cameras had nothing to do with the music. They set a new level for pandering, a clear at tempt to reach out to the audience through nonmusical means, as if to say, “I’m a great guy! We’ll get along whether you like this piece or not.” Throw in a white piano, and we might as well have been watching Liberace.

What’s disturbing is that Mr. Lang has astounding talent, a quality apparent from the moment he burst on the musical scene, at least so far as his technical ability was concerned. His teacher at the Curtis Institute of Music, Gary Graffman, says that far more than simply a dazzling technique was in evidence when he auditioned for Curtis at age 13. “I listened to him with [Curtis faculty members] Claude Frank, Leon Fleisher, and Seymour Lipkin. Frank and Fleisher were Schnabel students. They’re not going to be impressed just because some kid can play a Hungarian Rhapsody. It was clear that he is someone special.” Can Mr. Lang rein in his stage movements if he wants to? It looks as though he can. Following the pianist’s recital in Philadelphia’s Kimmel Center last week, Mr. Graffman noted, “[Lang Lang] hardly moved around at all. There were none of those kinds of fireworks. His movements were just normal. Even the local critic, who has been critical in the past, gave him high praise.”

If this is true, it would appear that he was really just mugging for the camera, putting on a show for the folks at home. And if Lang Lang can discipline his gestures, what about his interpretive indulgences? He plays Mozart, Schumann, Chopin, and Liszt with much maturity in his recently released first studio solo disc, called “Memory.”Yet in performance he often distorts the music with a sudden burst of energy, or by milking a phrase, or by distorting tempos.

The issue has implications for the future. One concern is that Mr. Lang may be setting a negative example for younger pianists. Will others hope to replicate his box office appeal by putting on displays? A veteran artist manager, Maxim Gershunoff, author of the memoir “It’s Not All Song and Dance,” points out that showmanship can stunt musicality. As he said in an interview with The New York Sun, Mr. Lang has gained so great a degree of notoriety that it may be too late for him to develop into a serious artist.

Even before the PBS broadcast, Mr. Lang took a few knocks.Veteran pianist Earl Wild, something of a showman himself, once called Mr. Lang “the JLo of the piano.” But the fact is the youngster now has a brand name that reaches beyond the classical world. Mr. Lang’s story of familial sacrifice back in China on behalf his career plays beautifully to television producers, who are not known to go giddy in the presence of classical artists. (One who flirts with the camera may be a different story.) And his record company, Deutsche Grammophon, is fueling a rivalry between him and another of its artists, Yundi Li, who happens to be a gifted Chinese pianist about the same age as Mr. Lang, in hopes of boosting sales of both.

The classical music world is full of cynicism, but could it be that Lang Lang is taunting the musical establishment with his willful interpretations? That he wants to keep the audience on edge with an element of unpredictability? That he knows the limits of stylish musicianship full well but wants to prolong the suspense over whether he will turn into a real artist? No matter what the motivation, the result is certain: There is a tension to a Mr. Lang appearance that sells tickets. Just try to get one at Carnegie Hall tonight.