Asked the inevitable question about how things were going on the set of “Hairspray Live,” which NBC will air Wednesday night, director Kenny Leon just laughed. And laughed. Then laughed some more.

“It's very scary,” Leon said. “But it's going very well.”

The mix of nerves and confidence is understandable.

“Hairspray,” the brilliant, buoyant musical based on the John Waters film about a popular Baltimore TV dance show and a full-sized teen's efforts to integrate it, will be performed live. It's a risky, viewer-catnip concept that NBC pioneered in the mid-1950s with “Peter Pan” and “Cinderella.”

The network revived the format in 2013 to broadcast a live production of “The Sound of Music” that found about 18.5 million people tuning in. That was followed by a new “Peter Pan” and, last year, “The Wiz.”

The market for live musicals shows no sign of fading. Fox picked up on the trend with a live “Grease” at the beginning of this year. And NBC has already announced “Bye, Bye Birdie” as its next live musical in 2017, starring Jennifer Lopez.

Meanwhile, the back lot at NBC Universal studio in Los Angeles is hopping with stars and newcomers, including 24-year-old Baltimorean Unissa Cruse-Ferguson, who won a contest for a spot as a dancer in the “Hairspray” ensemble.

“It's epic,” said Leon, the seasoned, Tony Award-winning director who guided NBC's “The Wiz.” “I tell the cast it's a little bit TV, a little bit film — but it's also like the Super Bowl. Because I've done ‘The Wiz,' this time it's a little easier for me. I have a good idea of how it's going to flow.”

Maintaining that flow, and coordinating the 13 cameras that will capture it, requires expert timing.

“On ‘The Wiz,' everyone was in one space and we changed the look with LED screens,” Leon said. “For ‘Hairspray,' we're using eight or nine different locations, and 40 percent [of the broadcast involves] exterior shots on the street depicting 1962 Baltimore. We've got four or five seconds to spare between scenes. Nothing can go wrong.”

Helping to ensure that everything goes as planned are such veteran performers as Harvey Fierstein, reprising the drag role of hefty Baltimore housewife Edna Turnblad that he created on Broadway.

Kristin Chenoweth is Velma Von Tussle, the bigoted producer of “The Corny Collins Show,” which features carefully selected white dancers for the televised program. Jennifer Hudson is Motormouth Maybelle, host of the monthly “Negro Day” on that show and the source of major moral support for the integration-minded kids in “Hairspray.”

Other familiar names dot the cast, among them Martin Short as Edna's jokester husband Wilbur; Sean Hayes as the owner of a plus-size dress shop; Andrea Martin as prudish Prudy Pingleton; and Rosie O'Donnell as a gym teacher.

Among the fresh faces that will fill the TV screen is that of Maddie Baillio. She plays Edna's intrepid daughter, Tracy, who helps integrate the dance show and, along the way, teaches some lessons about self-worth. Fittingly for a musical with a big-break audition scene, Baillio was chosen out of 800 who responded to an open casting call in New York last spring (200 others sent in video auditions).

Cruse-Ferguson, who lives in Ednor Gardens and works with a Washington nonprofit and part-time for a Towson retailer, had a similar experience. She got the nod after auditioning with about 200 others at the Hippodrome in September.

“It has been really hectic in a great way,” said Cruse-Ferguson, who arrived a week ago for rehearsals. “The challenging part is not necessarily the choreography itself — that's not stressful at all. It's being thrown in right away as a newbie. It's like first day of school, new girl in classroom, midway through the semester. But I'm not falling short or falling behind. They're making sure I'm on my toes.”

An alum of the University of Maryland School of Theatre, Dance, and Performance Studies, Cruse-Ferguson quickly attracted the attention of Leon.

“She came up to me, eyes wide open, and the first thing I did was tell her, ‘Take the chewing gum out of your mouth,'” Leon said. “But during the first number we did, I thought, ‘Wow, she's totally talented.' There's no telling where she can go. She's our Baltimore angel, our good luck charm.”

Hudson calls Cruse-Ferguson “Miss Baltimore” on the set; the Grammy- and Academy Award-winning singer and actress used that greeting in an Instagram video-selfie she posted a couple days ago.

Cruse-Ferguson has received cordial welcomes and encouragement from other celebs in the cast, among them recording artist Ariana Grande, who has the role of Tracy's nerdy friend Penny Pingleton.

“She's so sweet,” Cruse-Ferguson said. “I would love to be able to dance on her upcoming tour. I'm not really about the flashing lights. I just want to learn more about the theater world, more about just bettering myself as a person and a dancer. I auditioned for ‘Hairspray' just for fun. I know I will have to work harder for the next one.”

Getting to Wednesday night's broadcast will be hard work enough. Leon noted that one cast member lost her voice a few days ago, and another was injured — all in the cause of getting things just right. Even the most experienced performers are feeling the Kenny Leon burn.

“Kristin Chenoweth, Harvey Fierstein, Martin Short — they all want to do better,” Leon said. “And I'm the guy who's going to tell the truth. I've been working with Jennifer Hudson, and when people see what she does with this role, they're going to go, ‘Whoa.' I'm just as interested in the young folks. Ariana Grande is a young music icon who wants to spread her wings.”

Speaking of icons, where's Waters as “Hairspray Live” takes shape? On tour. Wednesday night will find him in Colorado, performing his wickedly funny one-man show, “A John Waters Christmas.”

“I'm competing with myself,” Waters said. “So I'm taping [‘Hairspray Live'] and will watch it the next morning. I'll be the last person to see it. I hate that.”

If it hadn't been for the tour, Waters would have slipped into Wednesday's broadcast.

“They offered me a cameo,” he sad. “In the [2007 movie version of the musical], I was the flasher. I don't know if I would have been typecast this time. I'd love to play the rat that runs across the stage at the beginning.”

In a way, Waters will be represented after all, thanks to the production design by Derek McLane.

Shop fronts appearing in street scenes have names that give nods to the originator of “Hairspray” and actors who appeared in his movies. One is dubbed Waters Plumbing, which bears an extra sign: “Since 1946” (the year Waters was born). Another store, Bud's Duds, refers to Buddy Deane, whose Baltimore dance show on WJZ inspired “Hairspray.”

“That's very sweet,” Waters said of the set design. “I had no idea they were going to do that.”

Waters met with Baillio to give her pointers on the background to “Hairspray.” People new to the show “don't know the deepness of the Buddy Deane culture,” Waters said.

In addition to capturing a moment in pop culture when TV dance shows were a big deal, “Hairspray” gets much of its mileage from the issue of prejudice, racial and otherwise. Beneath the beat of the catchy music and lyrics by Marc Shaiman and Scott Wittman can be found messages that resonate widely.

“Tracy stands for any kind of outsider,” Waters said. “I think that's why ‘Hairspray' has stayed around so long. ‘Hairspray' is a Trojan Horse that sneaks into Middle America and spreads the message: Don't judge other people.”

For Cruse-Ferguson, there's an extra layer to that message.

“I'm so proud to represent Baltimore because you don't hear about too many awesome things that happen to the young African-Americans in Baltimore today,” she said. “All you see [on TV] is the projects, the bad neighborhoods, the people who are killing each other, the riots. There's way more to the culture — so much talent, so much drive, so much support and a sense of community.”

The young dancer sees “Hairspray Live” as having fresh relevance to her hometown.

“The show's message is that it doesn't matter what you look like, or where you're from,” Cruse-Ferguson said. “It's an amazing message and really nice for Baltimore to see right now.”

Millions across the country will be seeing it, too.

“I predict the largest number of viewers for any of these live musicals ever had,” Leon said. “This show is perfectly beautiful and perfectly timely. It's about race, class, size and sexual identity. It's a story inclusive of all folks. It's about what we can be. I think people are going to take this in. I hope it will make them feel good and loving and caring as we approach the holiday season.”

tim.smith@baltsun.com

Baltimore Sun reporter Chris Kaltenbach contributed to this article.