Mirren, who is becoming something of an expert on playing English royalty, creates an astonishing portrayal, by turns prickly and chummy, regal and regular, insecure and temperamental. She nails the fussiness and strange high-pitched voice but also reveals a frustrated yet resigned monarch quietly pining for a different life. Her quick changes often happen onstage with a new outfit and wig. But perhaps the best stitching is from Morgan, who nimbly fits in exposition and big swaths of history into a coherent and touching portrait of power and majesty. And, with Mirren, even ardent anti-monarchists will clap.