When she sang the heart-wrenching lyrics, "better off without them", a fan called out, "PERIOD", causing Billie to lose her composure and start laughing while singing.
Fans were absolutely living for her reaction, going off on Twitter.
"i know this song is really sad, emotional and meaningful to many people and obviously to @billieeilish but I think for now on everyone should say 'PERIOD' after Billie sings the lyric “better off without them," one fan wrote.
Yep, the girl who made Billie Eilish laugh on stage will forever be a hero.