Lorde and Charli XCX Work It Out on the Remix at Madison Square Garden

Brat summer is technically over, but brat fall is just getting started thanks to Charli XCX and Troye Sivan’s Sweat tour, which touched down in NYC with a very special guest.

During the Monday, September 23, show at Madison Square Garden, Charli, 32, surprised the crowd when she brought out Lorde for a performance of the “Girl, So Confusing” remix. In videos of the moment shared via social media, Lorde, 27, walked up on stage just as the second verse was starting, wearing an all-black outfit.

The “Royals” singer styled her hair in long waves to look like Charli’s and wore her coat draped off her shoulders as well, making it difficult to tell the two pop stars apart in the dim arena lighting.

The crowd, meanwhile, went wild, with the screams almost drowning out Lorde’s first few lyrics. (Attendees eventually calmed down enough to sing along with the duo.)

Monday’s concert also featured a surprise appearance by Addison Rae, who performed her song “Diet Pepsi” with Charli and Sivan, 29.

Charli and Lorde released the studio version of their “Girl, So Confusing” collaboration in June, shortly after Charli’s sixth album, Brat, debuted. The duet came after rumors circulated that the song was about Lorde, who has frequently been compared to Charli because of their similar aesthetics (though their music sounds very different).

“I was super jealous of the success that [‘Royals’] got, and that Ella got,” Charli explained in a May interview with Rolling Stone UK. “You piece all this stuff together in your brain, like: ‘She was into my music. She had big hair; I had big hair. She wore black lipstick; I once wore black lipstick.’ You create these parallels and think, ‘Well, that could have been me.’”

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One month later, Charli addressed the song again during an appearance on Bowen Yang and Matt Rogers’ “Las Culturistas” podcast, but she didn’t specifically say the track was about Lorde.

“I don’t think you become a bad feminist if you maybe don’t see eye to eye with every single woman,” she explained in June. “That’s not the nature of human beings. There’s a competitiveness between us. There’s envy. There’s camaraderie. There’s all of these different dynamics.”

When Lorde joined the remix, however, all the rumors were laid to rest — and so was her beef with Charli. In her verse on the track, Lorde explained that she turned down Charli’s previous invitations to go out because she was afraid of being photographed.

“I was trapped in the hatred / And your life seemed so awesome,” Lorde sang. “I never thought for a second / My voice was in your head.”

Lorde also shared her support for Charli when Brat debuted, writing via Instagram: “The only album I’ve ever presaved is out today … Charli just cooked this one different. So much grit, grace & skin in the game. I speak for all of us when I say it’s an honor to be moved, changed and gagged by her work. There is NO ONE like this bitch.”