What does it look like when a star is born? In the case of Ben Platt, the astonishing young actor who plays the title role in Dear Evan Hansen, it's a bit like an actual birth: beautiful but strange and wet, tinged with confusion and danger. Evan is painfully introverted; he has no friends in high school, and even the thought of talking to a girl he likes, Zoe (the poignantly unaffected Laura Dreyfuss), makes his palms perspire. Platt's performance extends that to his whole body; when he sings, his face often gleams with sweat. Yet the effect is not off-putting; Evan is immensely lovable, even when he makes terrible mistakes. He speaks in rushes of instant regret, as though frantically digging a hole to bury himself in, and his intense awkwardness is filtered through first-rate comic timing, high-wire dramatic acting and a gorgeously expressive tenor voice.