Anna Bulbrook, founder of the femme-centric Girlschool L.A. festival, knew that having Fiona Apple sing with Garbage’s Shirley Manson would be a viral moment at their show at the Bootleg Theater on Saturday. But she didn’t anticipate until the last minute just how topical the duet would become, thanks in part to Apple’s “Kneel, Portnow” shirt, a reference to Grammy president Neil Portnow’s post-show comment that female artists and executives need to “step up” in order to get ahead. The song the duo performed — a cover of Lesley Gore’s 1963 hit “You Don’t Own Me” — tied in thematically to the moment as well. (Portnow has twice walked back the comment and announced a task force to promote “female advancement” in the Recording Academy and the industry.)

“Fiona texted us, ‘Should I wear this shirt?'” Bulbrook says. “We were like, ‘Oh my god.’ She changed three letters around and trended on Twitter on Super Bowl Sunday — this woman is really a special person.”

That sentiment was shared by Manson. “She walked into the door for rehearsal, then I saw her, it was like such a love scene in a movie where everything slows down and we were moving towards each other in slow motion,” Manson recalls to Variety. “I was engulfed in this incredible euphoria. I really believe Fiona has the best voice of any white female artist over the last 20 or 30 years, so to get to sing with her was just off the f—ing charts.”

Asked how the duet came together, Manson recalls, “Anna slyly, with a wry little grin playing on her lips, said, ‘How would you feel about me approaching Fiona Apple?’ I was like, ‘Are you kidding? I would be over the moon, but I don’t think she’ll do it.’ At around midnight she texted me in a frenzy, ‘Fiona is in.’ I think my belly flipped over — in that lovesick way,” she laughs.

Considering the scarcity of Apple’s live performances, “I don’t think any of us believed it was going to happen until she was sitting on a stairwell during Shirley’s set,” Bulbrook admits. “There was one song left and I was like, ‘Okay, she’s still here, this really is going to happen. When she finally walked onstage I think I put my hands on my knees and took some deep breaths. I was like, ‘This is really happening right now.’ Sometimes you just have a crazy idea and you just have to put it out there and the universe mails you a beautiful gift.”

For Manson, an outspoken proponent for women’s rights long before the #MeToo movement arose, Apple’s presence was galvanizing.

“I think all the women felt empowered by her presence there,” Manson says. “She is a woman of great integrity and she’s also incredibly punk rock — and it’s so peculiar because it comes out of this tiny little singer; she’s so slight and unassuming and quiet, and yet she has this incredible rebellious streak in her. I felt like all the women in the room thought, ‘Yeah, we can take the next step — and that next step is some action.'”