The reason for the comprehensive offering with H&M (and for including so many of her greatest hits) is also because, as McCartney puts it, “I’m not an elitist designer, and I’ve always really struggled with the fact that the majority of people who love my stuff can’t get my stuff because of the price point.” Plus, the ability to bring the lessons she’s learned from working on her own brand to fashion houses working at a bigger scale—hence her strategic alliances with multiple luxury conglomerates—has always excited her. “Obviously, when you’re working with the finest materials, you’re working with innovators, you’re growing mushrooms in labs, the price points are higher,” she continues. “But my goal is to infiltrate from within, and to show people that they can work this way. Why do you think I went into bed with Kering and LVMH? It’s like, if I can do this, you can do it. I feel like I’m almost like a research lab to show people that you can do this, at every level.”

Indeed, what is most astonishing—as H&M’s top creative advisor and designer whisperer Ann-Sofie Johansson tells me while leafing through the racks of clothes before McCartney’s arrival—is the level of care that has gone into making every piece as responsibly manufactured as it can possibly be. There are labels proudly displayed next to every piece that outline the materials used—organic cotton and silk, circular viscose, wool sourced from farms with strict animal welfare guidelines, textiles made from recycled feedstock—as well as information on the various innovative fabrics and techniques they tapped to make it all. “We have a third-party certification on many of them, so it’s not like we’re just saying it,” Johansson notes. “We work with a whole range of different outside organizations for that.”

Photo: Sam Rock / Courtesy of H&M

Photo: Sam Rock / Courtesy of H&M

It would be easy to dismiss the efforts of a retail giant like H&M—whose business model, some would argue, is fundamentally incompatible with sustainable principles—to do all this. But at a moment when a vast number of brands have rolled back their sustainability efforts (many for political reasons), it’s cheering to see a retailer double down on those efforts: Alongside the collaboration, H&M is launching an Insights Board with McCartney to further that conversation, and by 2030, its target is to be using 100% recycled or sustainably sourced materials. “We have some tough goals, but we’re continuing with our goals in a very transparent way, and we’re trying to make it as big as possible,” says Johansson of applying the lessons learned through their partnership with McCartney to the brand’s projects more widely. “Some of the things are harder to scale, but we can apply it, of course, to more of our collections. That is usually how it works for us: We do it for a smaller, more limited [offering], and then we can scale it up.”

As for how McCartney sees it: “The reason for me to do it is to go, okay, let’s start a conversation,” she says. “Yes, this is fast fashion: it’s not perfect. Often, it’s shit, but we can make it less shit—sorry for my language. We can make positive progress. It can be better. That makes me so excited.”