“It was a risk,” says Stella McCartney, recalling her decision to collaborate with H&M in 2005. It’s an overcast March morning in a London riverside event space, and the designer is sitting in her uniform of gray boxy tailoring and a T-shirt, sipping on an oat flat white and looking out to the Thames a little wistfully. “But I’m not averse to risk. I’m a risk-taker every day in my job, and how I come at this industry is a fucking risk. So I’m never afraid of that.”

It feels almost quaint to imagine now, but McCartney is right: Back then, it was a risk for a fashion designer of her caliber to do a high-street collaboration. She’d launched her own label just four years prior, and had already planted her flag as the industry’s most outspoken voice on ethical and cruelty-free manufacturing. At that point, the only person to have done a high-street collaboration of this nature was Karl Lagerfeld the year before. “It’s funny, I feel like in my career I follow Karl Lagerfeld. Though obviously, he’s dead, so I don’t really want to follow him in that respect—not right now, anyway,” McCartney says, drily, pointing out she took over Chloé from the fashion legend in 1997. “Karl did the first [H&M collaboration], and nobody had really done them. Everyone was a bit like, ‘Oh, controversial!’ So I thought it was quite funny to follow him in that as well. I thought it would be quite annoying to him, in the fun, bantering kind of way he and I had. But yeah, it was a risk.”

A risk that paid off: Looking back at the headlines from the time, the release of McCartney’s collection sparked an unprecedented frenzy. “McCartney mania,” The Guardian wrote of the scene at H&M’s Oxford Street flagship on launch day, while The Independent described it as a “Stella stampede” and British Vogue as a “shopping riot”; this was still two years before Kate Moss’s Topshop collection brought Oxford Circus to a complete standstill, mind you. “I remember it was on the cover of the Financial Times, people properly fighting each other, like pulling pieces out of each other’s hands,” McCartney recalls, with a chuckle. So it feels like a full-circle moment for the designer that now, just over 20 years later, she’s dropping a new collection on May 7 with the Swedish retail powerhouse—one that feels almost like a miniature retrospective of her greatest hits over the intervening years.

“I really wanted to revisit the Stella wardrobe, the icons,” says McCartney of the collection, which spans a broad swath of categories, from sharp tailoring and eveningwear to shirting and denim. Standout pieces include an oversized trench coat cut from Regenerative Organic Certified cotton, a faux-snakeskin cropped bomber coated with a glossy layer of recycled frying oil, and hoodies and T-shirts with airbrush horses recalling the saucy spray-painted details from her spring 1999 collection for Chloé, as well as her horse-themed collection for the house two years later. Oh, and a riff on the cut-out, crystal-studded jeans she debuted in the spring 2023 collection for her own brand, originally worn by Bella Hadid on the runway and here with 80% recycled-glass crystals; they’re priced at $169, and are sure to sell like hotcakes. (One imagines that the affordable versions of her signature Falabella bags, here with the chain detailing in recycled metal and priced between $99 to $219, will fly off the shelves too.)

There’s also a riff on McCartney’s iconic “Rock Royalty” T-shirt, which she famously wore to the “Rock Style”-themed 1999 Met Gala alongside Liv Tyler, having picked up a three-pack of white Hanes tanks that morning and taken them to Little Italy to be customized as a cheeky nod to the pair’s famous rocker dads. (McCartney adds that she particularly loves it when people dress up in those looks for Halloween, and that she and Tyler send each other photos any time they spot someone recreating it.) She’s revived the piece a few times in recent years; just the week before we meet, I see the rock musician Hayley Williams wearing it on stage. Why does she think its appeal is so enduring? “I think it shows the spirit of the brand, it shows the humor of the brand, it shows that we’re still alive after 25 years. That’s a miracle when you think about it,” McCartney explains. “I try to use humor in the brand when I can, because there’s a very serious subject matter underneath everything I do—you have to have a lightness as well.”

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.”

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.”

The collection comes accompanied by a campaign shot by Sam Rock, featuring Angelina Kendall, Adwoa Aboah, and Renée Rapp alternately rolling in a field of grass and posing against the stark white backdrop of a photographic studio. (“They’re all mates of mine,” McCartney says of the casting. “And they’re women who have more to bring to the table than just how they look—they have amazing minds, too.”) It’s a reminder that the collection is just very cool—I can already picture the pieces that friends and colleagues will be snapping up. In the process of writing this story, multiple Vogue editors recounted to me the stories of the beloved H&M x Stella pieces they picked up back in the 2000s, and which still sit in their wardrobes today, in particular the jeans with zipper pockets: “I used to wear them with an elongated but not oversized V-neck sweater from same collab, with a little tie-dyed cami underneath and mid-heel pumps,” Nicole Phelps, Vogue Runway’s global director tells me. “I felt very chic.” Even Johansson arrives to meet me in a beaded silk jacket she bought while working as a womenswear designer for H&M back in the 2000s; it still looks as relevant as the day it first hit the shop floor. I somewhat inelegantly describe this strategy to McCartney—of surreptitiously bundling these sustainability credentials into highly covetable clothes—as similar to how you might put a pill in peanut butter to get your dog to eat its medication. She reacts to this so enthusiastically that she nearly knocks over her coffee. “I love that! That’s a T-shirt right there. The pill in the peanut butter. When that T-shirt comes out, you’re going to be like, ‘How dare she?’”

And she’s equally excited to see what people buy, hoping that a younger generation than her typical customer will buy items from the collection; it will be thrilling, she says, to spot people wearing pieces on the street. Will she be staking out the Oxford Circus store on May 7? “I would love to observe,” she says. “Maybe I’ll put on a disguise.” Perhaps she could add some last-minute sunglasses and wigs to the collection, I suggest. “Actually, Kenneth, can you block out my diary? I want to go and walk around an H&M store… I want to hear when people love it. And I want to hear when people hate it, when they slag me off. I’m fine with both.”

Most of all, she hopes that the partnership will encourage other brands with H&M’s global reach to consider how they, too, might do things differently. “It’s really hopeful, but it’s also really annoying,” says McCartney. “Because if I can do plant-based and not kill animals and not use animal glues and all the chemicals and all the cancerous tannery chemicals that are involved, why are all of the bigger, cheaper brands not doing it? And why are the luxury brands not doing that? What excuse do they have?” It’s on this subject that McCartney, already a whirling dervish of energy, becomes most animated. She adds, breaking into a wide smile: “It’s a really exciting, proud moment.”