Bodybuilders from Chicago gym were recruited to appear with Chappell Roan at Lollapalooza

CHICAGO (CBS) -- At Lollapalooza on Thursday evening, Chappell Roan's main stage performance featured a boxing ring set, complete with a punching dummy and bodybuilders lifting weights.

It turned out the bodybuilders—who lifted barbells and dumbbells onstage as the crowd danced to "Hot to Go!"—were recruited from a gym in Chicago's North Center neighborhood. Lawrence Scott owns Rockwell Barbell , 2861 N. Clybourn Ave., with his fiancée, Katie Nguyen.

"The last 48 hours have just been a pinch-me moment," Nguyen said.

Scott said a few weeks ago, they got a call from a producer at Lollapalooza who was coy about some of the details of what they were going to be involved in.

"The producer said that there's an up-and-coming artist that wanted to have people lifting weights during the performance, and that, quote, 'The people needed to kind of look like us,'" said Scott. "And so he was describing us as, you know, unique, tattooed, more muscular, maybe not like your average Joe—whatever that means."

Scott said the producer asked him if he could find six to eight people who fit that description to lift weights during a Lollapalooza performance, but did not let on right away that they would be onstage with Chappell Roan.

Scott and Nguyen themselves were among those who ended up onstage for Chappell Roan's performance Thursday. Scott said in the time leading up to the performance, he made sure to eat right and to keep training without missing any workouts.

When the time came for the big show, Scott said the highlight was walking out onstage and getting to the weights. But it was even better when the guitar, drums, and vocals kicked in and all the lifters got into a rhythm right along with the music—as they do at the gym every day.

"It was pretty nerve-wracking just knowing that we were going to be there, period, because it was such a big event in Chicago," Scott said. "But once we there, backstage, trying to get a glimpse of how many people were actually there—and then you hear that amount of people start to chant, 'Chappell!' then you start realizing how just out-of-this-world it is," he said. And then, you know, actually walking out in front of that was an entirely different thing."

The bodybuilders were asked to act like the gym was exactly where they were.

"They said, 'Just act like you're working out in the gym,' so that's what I tried to do," she said. "I'm sure I looked very robotic, but I was like, 'Just look at the tops of people's heads. They don't have eyes. Just keep doing your own workout,'" she said.

Other bodybuilders from the area were also part of the show—including some from Quad's Gym at 3727 N. Broadway in East Lakeview, one from Rise Gym and Gurnee, and another from a gym in Naperville.

"We all became really good friends really quickly, because we all sort of share the same passion," Scott said.

Nguyen said taking part in a Chappell Roan show was, to say the least, far from something ordinary.

"I'm usually not in front of anything. I'm always just around," she said. "So it's just a crazy experience."

Rockwell Barbell also sent one of their big guns to perform with Chappell Roan at Lollapalooza—Inez Carrasquillo, the current titleholder of North America's strongest strongwoman.