This past spring, you couldn’t miss her.

Commanding 4,000 square feet of premium Soho air space and wearing nothing by CK underwear, the indie rapper Chika gazed knowingly from Calvin Klein’s massive billboard — just like Kate Moss and Kendall Jenner before her.

But the 22-year-old musician’s proudly plus-size body type felt like a rebuke against the brand’s traditional muses and their famously skinny silhouettes.

The recent ad’s aftershocks included a feature in Time magazine, an InStyle interview and — thanks to a slew of Instagram tags — millions of digital impressions. But while Chika called her campaign coup a “happy surprise,” it was actually a deliberately canny move from Calvin Klein HQ.

Once the chicest name at New York Fashion Week, the brand didn’t even bother to present this past February nor is it on the show schedule that begins Friday.

Rather, Calvin Klein has recently slipped in its stilettos thanks to an ill-fated allegiance with designer Raf Simons, the beloved Belgian artiste who was named chief creative officer and lead designer in 2016. Simons’ collections were Vogue-lauded sensations but also retail duds thanks to their futuristic shapes and menacing graphics, many licensed from Warhol’s “Death and Disaster” series.

When Simons left the label in December, parent company PVH called his’ two-year tenure a “fashion miss,” and retail analysts estimated his otherworldly and sometimes just odd creations cost the label a whopping $240 million.

PVH stock plunged 7.4 percent in May. Calvin Klein shuttered its Fifth Avenue flagship and skipped the costly — but, in terms of high-profile publicity, major — Met Gala, where it used to host a table loaded with starlets including Margot Robbie and Emma Watson.

It seemed like a death knell. But some experts argue it could be a fresh start and a chance to shake off the cobwebs.

“Letting those things go is actually quite savvy,” says Tyler McCall, who analyzes retail strategy as editor-in-chief of Fashionista.com. “At first, there was a real sense of loss. Calvin was so legendary! But the brand pivoted quickly into what works: the underwear in extended sizing, the nostalgia for the ’90s, the push for diverse bodies in casting.”

Calvin Klein, once known for being a major trendsetter in youth culture — creating often controversial waves with ads starring a 15-year-old Brooke Shields, a skeletal Moss, a muscle-rippling Mark Wahlberg — is finally catching up to Gen Z’s more inclusive, individual idea of cool.

“Contrast that with a brand like Victoria’s Secret, who can’t acknowledge that women exist above a size 12. They very publicly excluded trans women and plus-size women from their runway. And now, their sales are tanking,” McCall adds. “Meanwhile, Calvin Klein . . . is actually listening to [young shoppers].”

According to company sources, the brand’s new strategy includes recruiting an invisible grid of “micro-influencers” (read: fun but not necessarily famous Instagrammers) to weave a new fan base for the brand.

The company’s chief marketing officer, Marie Gulin-Merle, told The Post: “We believe the most compelling and engaging campaigns are those that embrace not just diversity of race, body type, sexual orientation or gender identity, but also diversity of opinion and experience.”

That may explain why the new “#CKPartners” include dozens of plus-size women and men, along with sometime-models such as mental-health blogger Elena Sanchez, Sikh tailor Devkaran Singh Mattakul and disability advocate Kate Virginia posing in her wheelchair.

Of course, reliable thirst traps like Bella Hadid and Naomi Campbell sprawl across much of Calvin Klein’s billboard and Instagram real estate — but now they’re joined by trans bombshell Indya Moore and queer pop icon Beth Ditto, who smolders in plus-size lace lingerie.

Can embracing the full human spectrum, and shedding the waif look for good, save CK One from being CK Done?

Current numbers give a cautious thumbs-up, with the brand’s luxury fragrances claiming a quarter of the spots on Amazon’s bestseller list and its social-media followers surpassing American fashion titans Michael Kors and Ralph Lauren.

But the brand needs to follow through on its promise of inclusion by spotlighting more than one plus-size model at a time, whether it’s on a building or just a handheld phone screen.

As Essence beauty director Julee Wilson has said, inclusion “isn’t just right, it’s good business. Once brands understand the profits they are blatantly missing, hopefully things will get better.”

And if Calvin Klein likes anything more than getting cool cred, it’s getting back those missing profits.