Architects frontman Sam Carter stopped the show at the Lowlands Festival in the Netherlands to berate the culprit with a furious rant.
As Carter went on to explain, he wasn't sure at first whether or not to say anything about what he'd witnessed. "I'm gonna say it", Carter said.
"I saw a girl, a woman, crowdsurfing over here, and I'm not going to fucking point the piece of shit out who did it, but I saw you fucking grab at her boob, it is fucking disgusting and there is no place for that shit".
"It is not your f**king body and you do not f**king grab at someone".
Over the years, there's been lots of conversation surrounding the rampant sexual assault that occurs at concerts and music festivals, so the fact that Carter chose to speak out when he witnessed it sets an incredible example for artists and concertgoers alike.
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"I saw a girl, a woman, crowd-surfing over here".
Responding to positive comments online, Carter later tweeted: "There's no room for this at any kind of show". When we have more bystanders, both male and female, coming forward to speak out, these incidents will more likely become a thing of the past, making concerts and festivals more enjoyable for everyone. He couldn't see what I was pointing to and it was still happening I left the stage and walked straight for them, my mind an emotional blur. "Let's keep this a safe f*cking place", he shouted before the band started up again.
Clips of Carter's speech were shared on social media and drew widespread praise.
During one of the songs, Architects lead singer Sam Carter noticed a woman crowd-surfing towards the front.