Opening for Florence and the Machine, Boucher walked offstage after performing "World Princess Part II." "We just had a really disturbing thing happen to us today, so sorry if my voice is shaking, it's just kind of a fucked day...trying to keep it together," she said in introducing the song.
Brooklyn Vegan reports that the house lights came up following her departure.
As of yet, neither Grimes nor her label 4AD has issued a formal statement about the incident.
Watch fan-shot video of the stage walk-off below.
UPDATE (6/16, 7:15 p.m. EDT): Grimes has acknowledged the incident on social media, though details behind the walk-off remain vague. She tweeted: "I will explain what happened at Barclays once I can safely and legally do so." She then asked fans and media to not speculate about the situation based on unreliable sources, but thanked those who have offered their support.
I will explain what happened at Barclays once I can safely and legally do so.— Grimes (@Grimezsz) June 16, 2016
In the meantime "someone from Reddit" or fan accounts are not credible sources. Speculating about my mental health is not news. Thanks.— Grimes (@Grimezsz) June 16, 2016
and thanks to all of you who are being super sweet 🐿🐿— Grimes (@Grimezsz) June 16, 2016
UPDATE (6/17, 12:10 p.m. EDT): Grimes has also announced that she'll have a new song titled "Medieval Warfare" coming up in the new Suicide Squad film.
In happier news: I have a new song coming out on the suicide squad soundtrack!!!! It's called 'medieval warfare' ^_^ dreams becoming realiti— Grimes (@Grimezsz) June 17, 2016