Each week on Fosse/Verdon, Michelle Williams is giving one of the most fascinating vocal performances on TV. As Gwen Verdon, she adopts a theatrical, mid-century, pseudo mid-Atlantic lilt, full of flourishes and misplaced stresses that vary in strength and timbre as the FX miniseries hopscotches around Verdon and Bob Fosse’s creative and romantic history. In the show’s penultimate episode, a showcase for Williams set around the premiere of Chicago, she also had to pretend to lose her voice. The real Verdon struggled to perform the musical’s songs, eventually dropped out of the show, and went through vocal surgery after infamously swallowing confetti during a performance. While

she had a dialect coach, Williams figured out how to play Verdon’s vocal disintegration on her own.

Verdon’s voice, Williams explains, “was the things that I started worrying about first, because if you are thinking about your voice while you are acting, you’re not able to be fully present.” A little over two months before shooting Fosse/Verdon, Williams started working with Deborah Hecht, a voice teacher at Juilliard who’d coached her before. “She’s an amazing teacher, and I wish I was a Juilliard student,” Williams said, noting that they’d meet three to four times a week on the specifics of Verdon’s accent. “She had this very unusual breathy, raspy voice, but it was still resonant,” Williams said. “You literally have to hold your mouth in a different place, and move your tongue and your lips more than you normally do. To get that to a point where it feels seamless just takes so much practice.”

Fosse/Verdon skips between periods in the title characters’ careers, and Williams wanted to make sure her performance aged with the character. To vary the voice, she had several clips from different moments in Verdon’s career on reference. “I have an iPod with me, and between takes, it was my idol,” Williams said. “I would listen to her all the time, I would watch her all the time, she was always in my ear or in front of my eyes.” She watched a clip of Verdon and Fosse on a TV show for scenes in Verdon’s 30s (when they were first in love), another of them on Dick Cavett for scenes in her 40s and 50s, and footage of Verdon in her 60s for scenes later in the show. “There is one clip that I love, because she’s accepting an award and she’s just pausing for breath all the time, it’s becoming more shallow and it’s moving to her chest as the result of aging, smoking,” Williams said. “I based it on what was in front of me, what I heard and what I saw, as much as I could. I wanted to be faithful to who she was and faithful to the people that knew her.”

Another crucial source was Verdon’s daughter with Bob Fosse, Nicole, a co-executive producer on the series who helped Williams understand that her mother’s private life was something like her public persona. “She said what could be hard, as her daughter, was when [she] was doing ‘Gwen Verdon,’” Williams said. “She loved to be who people wanted her to be, and that performer lived onstage and offstage.”

One of the most technically impressive scenes in the show comes after Verdon’s vocal surgery. Fosse calls her with the news that, after Liza Minnelli replaced her as Roxie in Chicago, the New York Times re-reviewed the show and gave it a better write-up. As Verdon, Williams had to lay into Sam Rockwell’s Fosse over the phone, while still acting as if she was just out of vocal-cord surgery. “I had been experimenting for a couple of weeks, privately, with what I thought it might sound like,” Williams said. “And then on the day, I took it out of my little box and I asked [director] Tommy Kail if it was okay.” Kail’s direction in the scene, she added, was to “think about what it costs her to say each word, and then think about when the cost doesn’t matter anymore, that the words are more important than the damage or the pain that they do.”

Throughout the Chicago episode, a version of Gwen Verdon appears as a sort of emcee to the proceedings, narrating for the audience, winking at the camera, and singing the song “Razzle Dazzle” over a montage of Verdon and Fosse wooing a man from an adoption agency. “I thought of it as not Gwen, but Gwen’s fantasy of herself,” Williams said of the character. She wanted to nod to Verdon’s love of Charlie Chaplin and harlequins in the emcee character’s sensibility, throwing in some of her own whimsy along the way. “I started to think of her as like the Little Prince, somebody who’s alienated and hasn’t had a show for years and is lonely, ready to entertain,” she said. “It was a character that I felt outside of reality and outside of Gwen herself, because it’s like Gwen’s imagination.”

Concept aside, Williams promises it was also very fun to perform. “I was tap-dancing on a piano! It was like I’d died and gone to heaven.”