“Dance like your mama’s watching!”

It’s just two weeks before the Dec. 7 debut of NBC’s “Hairspray Live!,” and choreographer Jerry Mitchell is (cheer)leading the troupe of performers through rehearsal on a soundstage on the Universal lot.

“You Can’t Stop the Beat” is the musical’s show-stopper, the final song, which features the entire dream-team cast — from Jennifer Hudson (Motormouth Maybelle) to Kristin Chenoweth (Velma Von Tussle) to Ariana Grande (Penny Pingleton) — meticulously assembled by executive producers Neil Meron and Craig Zadan. It’s a high-energy number, which Harvey Fierstein (Edna Turnblad), who wrote the teleplay, has dubbed “You Can’t Stop to Breathe.”

Like all the Tracys who came before her, Maddie Baillio was plucked from obscurity to play the role. Now Baillio (right, with Harvey Fierstein) stars in a musical in which she appears in every scene. “When she dances, it’s infectious,” says choreographer Jerry Mitchell. “You’ll fall in love with her.” Courtesy of Colleen Hayes/NBC

“That number will kill you if you’re not careful,” Fierstein says, kiddingly (we think).

Broadway veteran Mitchell is a high-wire bundle of energy — singing and dancing as he coaches the backup dancers as well as the theater legends. Martin Short (Wilbur Turnblad), who’s busy cracking jokes with Fierstein, his dance partner, misses a step — and blames Mitchell: “Your judgment and your glaring scares me.” Counters the choreographer: “You can’t do that on live night.”

Just off-set, Grande, clad in a “Girl Power” sweatshirt, is rehearsing her own moves with one of the assistant choreographers. “I eat three times a day,” the tiny pop star promises one of the dancers, as her mother hovers nearby. Notes Zadan of the star: “She’s saying this is one of the best things she’s ever done.”

Executive producer Craig Zadan singles out Jennifer Hudson’s rendition of “I Know Where I’ve Been” as a standout moment. “When we cast her, I imagined what it would be like. The first time she did it, every one of those kids with her was weeping. They were hit with lightning.” Courtesy of Colleen Hayes/NBC

The $10 million production sprawls across Universal Studios — from a massive soundstage that houses the set for the neon-bright Corny Collins show and the laundry-strewn Turnblad home, to the famous backlot, where New York Street has been transformed into downtown Baltimore. Along with Mr. Pinky’s Hefty Hideaway and the Hardy-Har Joke Shop, the stores lining the block boast a series of in-jokes — nods to the show’s storied legacy — that include Divine’s Pet Food and Waters’ Plumbing, as well as Greenblatt’s Baltimore Crabs and Meron’s Used Cars.

Forty percent of the show will take place outside on the faux city streets, with intricate plans for the cast to be shuttled around in golf carts and passenger vans. “It’s amazing to be able to be out here and choreograph in 360 degrees as opposed to one proscenium,” says Mitchell. Still, he’s fretting about how the dancers will climb down from the balconies in time for the next section.

Then there’s California’s unpredictable winter weather to contend with. Fox’s “Grease: Live” faced rain in January, so this crew is planning for the worst-case scenario. “It’s going to rain on Dec. 7 and have 25 mph winds,” says director Kenny Leon, then adds: “Let’s just hope it doesn’t.”

“We’re going to pass influenza around to each other, because we’re constantly hugging and touching,” jokes Kristin Chenoweth. Adds Baillio, “Harvey texts me every night to make sure that everything’s going smoothly and that I’m happy.” Courtesy of Colleen Hayes/NBC

Given the popularity of the movie-turned-musical-turned-movie, there are still surprises in store. Some cameos have already been announced — including appearances by the original Tracys, Ricki Lake and Marissa Jaret Winokur — but Zadan promises more to come. “For people watching the show, they’re going to go, ‘Oh, my God, is that so and so?’” he says. “You’ve got to keep your eyes open on this one.”

Amid all the dancing and singing, there is a sense among those involved that this musical, with its message of racial unity, is a particularly well-timed one.

“It’s a story about integration in the ’60s, but I think it’s a metaphor for the times that we live in,” says NBC entertainment chair Bob Greenblatt. “While it’s broadly comedic and heightened reality with Edna Turnblad being played by a man, there’s also some really important and serious drama. There’s even a protest march and an anthem about civil rights. All that comes together in a way that’s more important than how much money we make and how many viewers tune in.”