It's the hottest show in London's West End, and no wonder: Equus features big-screen boy wizard Harry Potter 17-year-old Daniel Radcliffe to you Muggles blinding horses, stripping naked, and sexing up a stable girl. But at a recent preview performance, the female-heavy audience was attentive and serious. ''I'm interested in the play,'' insisted 24-year-old Canadian Janet Fisher. ''It was very intense,'' said Meg Jones, 17, adding that she bought tickets because she's studying the Peter Shaffer psychological drama with her Swindon, U.K., theater troupe. And as for Radcliffe's seven-minute scene in the buff opposite actress Joanna Christie (the star removes his clothing in full view of the crowd, some of whom are seated on stage)? The theatergoers EW spoke to remained unfazed. ''The only heavy breathing was the sound of the old man asleep behind me,'' said Mary Mount, 29, of New York. ''I was more shocked by Harry Potter smoking than by seeing him naked.''