Emily Tyra thought she may have dozed off on set. When she woke up this past March in a Los Angeles emergency room with no memory of how she got there, it seemed like a practical explanation. She had just spent two years playing an ER resident on the CBS medical drama Code Black, after all.

“Am I in an episode?’” Tyra recalls thinking. “Am I being punked right now?”

The actor and dancer had been jogging earlier that day when she ran by a streetlight and was overcome by déjà vu, as if she had already passed it. Then an unfamiliar presence began lingering in her peripheral vision. So she went home, dropped to the floor and called her then-fiancé, music producer Adam Santucci, in a panic. Just as he arrived, Tyra went into a seven-minute seizure. An ambulance rushed her to the hospital, where a CT scan revealed the golf ball-sized tumor on her right parietal lobe.

“It was one of those weird, Lifetime movie kind of days,” Tyra says.

Five days later, Tyra underwent a craniotomy at Keck Medicine of USC to remove most of the mass. In addition to the usual anxieties that come with such a life-altering event, Tyra had a career concern: The location of the tumor—on the part of the brain responsible for spatial awareness and depth perception—raised the possibility that she could never dance onstage again. But just eight months after her operation, Tyra, 32, is high kicking her way through Signature Theatre’s sold-out run of the classic musical A Chorus Line.

“I’ve never met somebody like Emily Tyra,” A Chorus Line director Matthew Gardiner says. “To have gone through everything she’s gone through and to tackle everything beyond 100 percent, it’s really amazing.”

After the March 26 operation, which left Tyra with 13 screws in her skull, she struggled with balance and coordination. Within a week, though, she managed to walk around the block. Tyra went hiking a few weeks after that. She gradually began to regain confidence in her day-to-day life, even if she stumbled into a stranger or two at the grocery store.

It wasn’t until the pathology came back that Tyra learned the tumor was cancerous. Because the surgeon couldn’t remove the entire mass, she was advised to undergo six weeks of radiation—which she concluded 10 days before her June 29 wedding—and a year of chemotherapy.

As part of her rehabilitation, meanwhile, Tyra resumed taking ballet classes. Although Tyra had been focusing on television in recent years, she began her career dancing with the Boston Ballet and appeared in such Broadway shows as Nice Work If You Can Get It and Chaplin. Tyra accepts she likely will never again dance with the precision she did before the operation, but her considerable post-surgery progress in the dance studio proved to be cathartic.

“Dancing is an enormous part of who I am, [and] the idea that I would never be able to draw upon that skill set again was really devastating for me,” Tyra says. “So I was like, ‘Well, that’s just not going to happen.’ As little as I understand about the brain, what I do know is that it is an incredibly resilient organ and it will find a way to rehab itself.”

When Gardiner subsequently reached out about the role of Cassie in Signature’s revival of A Chorus Line, it wasn’t the first time she had been approached to play the character. The show famously unfolds at a New York audition, as dancers vie for a handful of slots in the chorus line of a Broadway musical, and Cassie—a former featured dancer humbled by a failed stint in Hollywood—is the closest thing the ensemble has to a star. But Tyra had always turned down the role, saying she didn’t want to “live up to the expectation of a thousand incredible dancer-actor-singers that had done it before.”

Then the hook of new choreography from Tony nominee Denis Jones (Tootsie) caught Tyra’s attention. More crucially, her health issues gave her a greater connection to the beleaguered character, who, like Tyra, returns from Los Angeles to the East Coast stage.

“This, on paper, looks like a crazy idea for me, having had brain surgery seven and a half months ago,” Tyra says. “But I was like, ‘I just completely get it. I know what it’s like to crawl back and ask for a place to belong.’”

After accepting the offer, Tyra connected with a neuro-oncologist at Columbia University in New York who could serve as her East Coast medical contact. Tyra still must manage fatigue and other symptoms brought on by her ongoing oral chemotherapy regimen, which won’t conclude until July, so she committed to treating her body “like an Olympian.” Throughout rehearsal and the first month of performances, she has eschewed a typical social life in favor of quiet nights in—saving her strength for the show’s kinetic ensemble numbers and Cassie’s protracted solo, “The Music and the Mirror.”

“I have to eat really healthy and go to bed really early, and I walk around the theater with, like, a gallon of water to drink every day,” Tyra says. “There were, of course, moments where I would come home and be like, ‘I should not have said yes to this.’ I was experiencing my own sort of psychodrama that nobody was really in on. But I would just take a deep breath and sit down and relax and think, ‘OK, I’m going to do this again tomorrow.’”

Gardiner hadn’t actually known about Tyra’s surgery when he pitched her on the role. But she opened about her recovery during a Skype conversation with the director, which left him confident in her self-belief. “She really wasn’t going to let any of this stop her from doing what she wanted to do,” Gardiner says. “There was never a moment where she said, ‘Can we end early?’ or ‘Can we take a break?’”

When Tyra took the part, she asked herself: “Am I OK with failing publicly as I rebuild myself?” Nearly halfway through the show’s run, though, Tyra feels she’s only growing stronger with each performance. When she steps onstage, she does so with a grateful skip in her step.

“I underestimated my ability to, first of all, get through this emotionally, and then physically I cannot believe what my body is able to do,” Tyra says. “It is the greatest rehab of my life.”

A Chorus Line runs at Signature Theatre through Jan. 5. Runtime is approximately 2 hours with no intermission. Tickets are sold out.