Joe Locke was so moved when he saw “Next to Normal” at the Donmar Warehouse in London last fall that he called his agent with a request. “I was like, ‘I want to do a musical so bad,’” said Locke, 20, who for two seasons has played the sensitive teenager Charlie Spring in Netflix’s L.G.B.T.Q. coming-of-age drama “Heartstopper.”Soon after, his agent said he’d gotten an email from the casting team of Broadway’s “Sweeney Todd,” and the show was looking for a new Tobias Ragg, an urchin taken in by the scheming pie-maker, Mrs. Lovett. “The easiest way to play him is that he’s a bit simple — he’s not a full egg, as the Irish would say,” Locke said in a phone conversation in early January from his Manhattan apartment, before one of his first rehearsals. “But I think he’s a very street-smart character who’s survived in a world where people like him shouldn’t survive.”

---

Persons: Joe Locke, “, ’ ”, Locke, Charlie Spring, ”, he’d, Broadway’s “ Sweeney Todd, Tobias Ragg, Lovett, ” Locke Organizations: Donmar Locations: London, Netflix’s L.G.B.T.Q, Manhattan