Mr. Badgley, 34, who played lonely boy Dan on the original “Gossip Girl” and now stars on the Netflix thriller “You,” hadn’t visited a gym in two years. He hadn’t taken a dance class in far longer.
But at a fashion shoot a month before, he had found himself moving in tandem with the photographer and missing dance acutely. So he reached out to André Zachery, his gyrotonics instructor and the artistic director of Renegade Performance Group, a contemporary dance company in Brooklyn. Mr. Zachery was willing to put him through his paces.
In the yawning dance studio, mirrors lined one wall. Ice-white tube lights glared overhead. Mr. Badgley had dressed for class in a villain-black T-shirt and shorts. A luxurious dad beard and a corona of mink-brown hair framed his face.
They began with a warm-up: stretches, lunges, isolations of the neck, shoulders, chest and hips. Roy Ayers’s “Everybody Loves the Sunshine” set the groove; Mr. Badgley, his brooding face etched into a frown, inhaled and exhaled in time, rolling his spine down and up.
Mr. Zachery integrated the stretches into a simple routine, and Mr. Badgley lumbering and somewhat stiff, like a bear who hadn’t fully shaken off hibernation, danced his way through the initial eight count, then repeated the steps again.
“All right, not bad,” Mr. Zachery said encouragingly. “You want to go a little faster?”
Mr. Badgley paused to tie his hair back with a blue-and-white bandanna. He asked to take it slow again. “As much as I love to move and I love to dance, it’s not a language that I speak regularly at all,” he said. “So even just getting into this feels great. But it also feels very clumsy.”
Mr. Zachery reassured him, gently countering Mr. Badgley’s perfectionism. “Be imperfect with this,” he said.
As Mr. Zachery prepared the next combination, the track switched to Donny Hathaway’s “The Ghetto,” and Mr. Badgley’s face stern face split into a smile. “This is one of my kid’s favorite songs,” Mr. Badgley said. “He loves classic soul.”
Last summer, Mr. Badgley and his wife, Domino Kirke, welcomed a son. (They also share custody of Ms. Kirke’s son from an earlier relationship.) On “You,” Mr. Badgley plays Joe, the sociopath next door. Joe has also had a son with his wife, Love (Victoria Pedretti), who has a body count of her very own.
In the third season, which premieres on Oct. 15, Joe muses about his new life in a Bay Area suburb. “Me, a boy and his mom, who is usually great, but occasionally murders people with her bare hands,” Joe says. “What could go wrong?” A lot, it turns out.
Mr. Badgley has some experience playing characters with dark motives. The final episodes of “Gossip Girl” revealed that Dan, the Deuxmoi of his day, had surveilled his friends and lovers, uploading their secrets to the pre-Instagram internet.
Making the show was, as Mr. Badgley described it, “an existential endurance test.” As a 20-something, he struggled with the glitzy ethos of the series. Fans’ failure to differentiate between him and Dan nagged at him, too. “I wouldn’t recommend fame to anybody,” he said. “It just doesn’t make anything better or help it make more sense. It doesn’t help you as a person.”
When “Gossip Girl” ended in 2012, he spent half of a decade shooting indie movies and touring with his band, MOTHXR. He wasn’t sure he wanted to return to mainstream TV and he had further doubts about Joe, a character who imprisons, tortures and kills women (and the occasional interfering man), all in the name of true love. Boy gets girl? Absolutely.
Still, he thought that “You” had something to say about the tropes of romantic love and the queasy nexus of desire, power and abuse. Many viewers responded a lot more swoonily and for a while Mr. Badgley took time to razz fans asking to be kidnapped. (“No thx,” he replied.) Now he tries to focus on the work itself, which he likens to a dance, “a torturous and ugly dance.”
Back in the studio, Mr. Badgley was trying to dance more beautifully. He can become overwhelmed by his own thoughts, he said, so Mr. Zachery introduced a guided meditation, occupying Mr. Badgley’s mind so that his body could move more freely.
As Robert Glasper’s cover of “Smells Like Teen Spirit” played, he had Mr. Badgley imagine himself at the beach, his body buoyed by the waves. They also played a game of avant-garde Twister, in which had Mr. Badgley had to keep either both hands and one foot on the floor, or both feet and one hand.
“Yo, man,” Mr. Zachery said approvingly. “You’re actually more in your body than you think.”
Finally, at a suggestion from Mr. Badgley, he switched the music to “Promises,” a mellow album from Floating Points, Pharoah Sanders and the London Symphony Orchestra. The two men began to move across the floor together, limbs slowly cartwheeling as they improvised. Politely, Mr. Badgley asked to turn the music up.
“Now we’re dancing,” he said, back arched, head tipped back, arms like wings. “It feels so good.”