The event was accompanied by sounds from DJ Fabienne, and celebrities in attendance — including Madonna and Ellie Goulding — also got their Stan Smiths signed. McCartney and Smith had their sharpies at the ready as Madonna, who was wearing her pair, propped her foot up on the table.

Fans snapped and filmed the moment and many were also heard gushing to McCartney, who was seated in a blue off-the-shoulder, vegan-leather dress next to Smith, about her sustainable ethos.

“I feel like a lot of people have responded very well and to have my name and my face alongside Stan is such a massive achievement for me on every level, it’s so iconic and to change something that’s been around and conventionally made out of leather is the new future of Stan Smiths,” McCartney said in an interview.

The vegan Stan Smiths feature perforated stars to the side, McCartney’s logo to the heel and a portrait of Stan Smith and Stella McCartney on the tongue of either foot. The sneakers, which retail for 235 pounds, lined the rippled concrete walls of the store.

Smith was busy signing shoes, but still spoke of his adoration for Stella: “she’s very creative and she was the one who brought up this unusual idea. While we’ve done previous collaborations, it’s the first time that I’ve ever done a shoe with somebody else completely involved. It’s totally vegan and totally amazing, so it’s a historic moment,” he said.

While McCartney has been busy designing the new shoe, she has also been busy preparing for her Spring 2019 ready-to-wear collection that will be showing at 10 a.m. on Oct. 1 during Paris Fashion Week, which runs from Sept. 24 to Oct. 2. When asked what to expect, McCartney simply responded, “just something very Stella.”