Over at the Kit Kat Club, the change in “Cabaret” is apparent in the show’s first moments. The Emcee, as played by the singer-songwriter Adam Lambert, is nothing like the Emcee as played by the film star Eddie Redmayne, who opened the current Broadway revival last spring after it transferred from London.

Lambert, in his Broadway debut, turns out to have theatrical chops: He’s lending his Emcee not only vocal shapeliness but also puckish warmth. The alienation so central to Redmayne’s interpretation has been replaced by humanity.

To Rebecca Frecknall, the show’s director, Lambert’s rock-star charisma was part of his appeal.

“What I didn’t anticipate was how naughty and funny he was going to be and how much he was going to enjoy that relationship with the audience,” she said by phone. “There’s also just something brilliant about what he brings of his personal identity to the role — having a queer, Jewish artist step into that space with that material.”

Set in Berlin during the rise of the Nazis, “Cabaret” starts out light and decadent and grows steadily, stealthily darker, with gut-punch songs like “If You Could See Her,” a satire of antisemitism. There’s also the ballad “I Don’t Care Much” — recently released as a single — which Lambert describes as “a real emotional moment” of “struggle with indifference” for the Emcee.

“They were so kind to raise the key to make it more of a torch song for me,” Lambert said.

With music by John Kander, lyrics by Fred Ebb and a book by Joe Masteroff, “Cabaret” became a hit with its original Broadway production in 1966. Lambert, 42, has known the musical ever since he was a theater kid growing up in San Diego, when his voice teacher showed him the movie adaptation.