SAM ROCKWELL & MICHELLE WILLIAMS

Rockwell, 50, who played George W. Bush in Vice, will portray Bob Fosse, the esteemed choreographer and director (Cabaret, 1972), in Fosse/Verdon (April 9). Former Dawson’s Creek star Williams, 38 (P.T. Barnum’s wife

in The Greatest Showman), joins him as Gwen Verdon, one of Broadway’s most celebrated dancers. The limited FX series traces their sizzling romantic and creative partnership.

What surprised you about Bob Fosse? Rockwell: I didn’t realize how great a dancer he was. If you look early on, he was on a par with Gene Kelly and Fred Astaire. He was an incredible dancer, and so was Gwen Verdon, obviously.

How daunting was it to emulate his dancing?

Rockwell: Michelle and I can hoof. We are pretty good movers, but this is a whole other realm. As Michelle said one day, “They look like normal people, but they get up and dance and they are superheroes.”

Did you study Gwen’s dance moments over and over again?

Williams: I watched on the internet late at night. If you haven’t seen her dancing, you really owe it to yourself to go to YouTube and find her. I love this dance that she does called Erbie Fitch’s Twitch. It’s deep in the internet. [You can find the video by searching “Gwen Verdon Erbie Fitch’s Twitch (1959)” on YouTube.]

How would you describe Fosse and Verdon’s relationship?

Rockwell: It’s a dense, complex story. Someone said Bob and Gwen were almost like twins in a way. They’re lovers, but they’re kind of Siamese twins, emotionally. I think they had a kind of June Carter/Johnny Cash, Ike and Tina Turner thing. There’s an artistic love there. It’s a beautiful relationship.

Michelle, would you ever do a Dawson’s Creek reunion?

Williams: Yeah. I’ve been waving that flag for a while. Why not? Although my character died, so I would have to be a ghost.