As the newly minted—and first female—CEO of the iconic denim brand Levi Strauss & Co., she got word that music legend Beyoncé would be name-checking the company in the title of a song off her recent album Cowboy Carter.

In turn, Levi’s launched its “REIIMAGINE” campaign with Beyoncé herself, who is notoriously averse to brand partnerships. 

“It’s sort of like a dream come true to have Beyoncé name a song after your brand,” Gass said at the Fortune Most Powerful Women Summit in Laguna Niguel, Calif., on Tuesday. “That’s a once-in-a-lifetime moment.” 

The song title wasn’t an advertisement or a partnership. All Gass and her Levi’s team got in advance of the album drop was “a little whisper” mere days before. “It was truly, completely organic.” 

But Queen Bey’s love for Levi’s goes way back, Gass told Fortune’s Ellie Austin, and their relationship is one that’s been nurtured over time. “She’s been a fan of the brand for decades—as we’ve been a fan of hers,” she said. Back in the 1990s, when Beyoncé was one-third of Destiny’s Child, Levi’s once outfitted the whole group—and the company still has a pair of Beyoncé’s jeans “in the vault.” 

New Americana

The Cowboy Carter song is spelled as “LEVII’S JEANS,” not Levi’s. A lawyer asked Gass if she was worried about trademark infringement, she recalled with a laugh. “I was like, are you crazy? This is a gift.”

Once the Levi’s team knew the song was coming, they shifted into action, changing all their social media handles to match the song’s stylization. “And then it just kind of went crazy.” Gass knew it was vital to seize the opportunity. “You don’t have these moments very often, obviously,” she said. “Once we saw the reaction, [we thought], maybe there’s something more here.” 

A few weeks after the album drop, Gass got dinner with Levi’s head of market, chief marketing officer, and chief product officer, and two top-secret key people in Beyoncé’s orbit. “We just sort of started to reimagine what was possible.” 

The 30-second spot featuring Beyoncé in a laundromat is actually a remake of a similarly popular ad campaign the brand did in the mid-’80s, Gass said. “The wonderful thing about Levi’s is we’ve got all this incredible heritage. So [we get to] take this and move it forward with one of the world’s biggest icons.” 

The entire campaign came together in five months, from the idea, to inking the contract, to doing the shoot. “Here we are, launched, and it’s been a great lesson with the team [about] how you can move with speed and agility and capture these moments, because they don’t come around very often.”

The Beyoncé campaign, Gass said, has led to over 2.4 billion impressions. 

Gass then motioned to her jacket, which was decked out in sparkles. “This was one of the many options that was created for Beyoncé for the shoot, but she did not choose to wear it,” she said. “So I get to wear it. But I will tell you, given all the feedback I’m getting at this conference, I suspect this will be in production. Stay tuned.”