Architects singer Sam Carter has been praised for calling out a man who allegedly sexually assaulted a female fan while she was crowdsurfing at one of the band's gigs.

The British metalcore band were performing at Lowlands Festival in the Netherlands when Carter paused between songs to talk about an incident he had just witnessed.

"I've been going over in my f***ing mind about whether I should say something or not about what I saw in that last song, and do you know what, I'm gonna f***ing say it.

"I saw a girl, a woman, crowdsurfing over here, and I'm not going to f***ing point the piece of s**t out who did it, but I saw you f***ing grab at her boob, it is f***ing disgusting and there is no place for that s***.

"It is not your f***ing body, it is not your f***ing body and you do not f***ing grab at someone. Not at my f***ing show. So if you feel like doing that again, walk out there and f*** off and don't come back.

"Let's keep this going, let's keep this a f***ing safe place for everybody, and let's have a f***ing good time."

Video footage recorded his passionate speech and showed the crowd cheering and applauding.

The incident comes two months after Circa Survive guitarist Brendan Ekstrom walked off stage to address what he believed was sexual harrassment.

A guitarist has been praised after he walked off stage mid-gig to stop what he thought looked like sexual assault in the audience.

Ekstrom said he saw a woman repeatedly rejecting the advances of a man at a concert in US city of St Louis.

Thinking “flirting doesn't look like that,” he stopped playing and walked off stage to confront the man.

He explained his actions to his fans on Twitter, writing: “Quick note to those who were at the show last night. I've been doing this for 20 years and I've never walked of stage during a song before.

“For almost a whole song I watched a guy stand a row behind a girl flirting and then trying to kiss her. It was hard to tell what was really happening. At times she seemed OK with his advances but after the second time of watching her push his face and hands away and try to turn back to watch the show I asked the security guard to go check on them.

“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. Security followed me. The man seemed dumbfounded when I showed up as if nothing was wrong. I don't know what happened after. I went back to stage to finish the show. Security took it from there."