Calvin Klein’s star-studded fashion show Thursday night referenced America and Hollywood, which I guess explains why designer Raf Simons decided to litter his post-apocalyptic barnyard set with tons and tons of popcorn — 50,000 gallons of it.

Popcorn covered the entire floor of the American Stock Exchange, where Simons’ third presentation for the brand was held. Celebs such as Margot Robbie, Nicole Kidman and Laura Dern had to wade through mounds of the stuff in their strappy high-heeled sandals, while the models wobbled in their space-age silver boots and heels atop all the puffed-up kernels.

“It took about three weeks to pop it all,” says Michael Bloch, owner of the Rochester-based Popcorn Charlie’s, which provided the edible decor for the show. “This was the first time we’ve ever done a fashion show,” he tells The Post.

According to Bloch, Calvin Klein had contacted Charlie’s before Christmas about providing a massive amount of its regular air-popped treats for its Fall 2018 show. It was by far the biggest order the company had ever seen: Three trucks had to transport the popcorn from Upstate to the Big Apple.

“I was nervous until about 4 o’clock, when I heard they arrived,” says Bloch.

Some guests delighted in the spectacle: “Twin Peaks” star Kyle MacLachlan giddily but perhaps not wisely gobbled popcorn off the ground for a Vogue Runway Instagram story. Others were … not as charmed. Fashion critic Vanessa Friedman, who otherwise called the show “extraordinary,” Tweeted a photo of her popcorn-dust-covered suede peep-toe platforms, grousing, “Turns out a popcorn runway is NOT good for the shoes.”

And it wasn’t just fashionistas worried about their footwear who considered the popcorn gimmick a faux pas. Some commentators complained about the waste. As one Twitter user wrote, “People: ‘Let’s fight world hunger!’ Calvin Klein: ‘I want the the runway filled with popcorn.'”