Halsey was pictured in the crowd helping wounded protesters at a George Floyd march in California.
Joined by her ex-boyfriend Yungblud, the Bad at Love singer, 25, could be seen cleaning the wounds of two men who had suffered injuries to the face at the demo in Santa Monica.
Marches have kicked off across the United States following the death of Mr Floyd, who was killed by a police officer that knelt on his back for five minutes.
The protest in Santa Monica was hit by looting and violence on Sunday.
Halsey was seen dressed in black and a pair of latex gloves as she stepped in to help the injured.
She brought along a first aid kit to the march.
Halsey, whose real name is Ashley Nicolette Frangipane, had taken to Twitter to speak about the horrors she saw there.
"Do not underplay these rubber bullets bc you have been told they are 'not lethal,'" she said.
"I had to bandage a man who looked like his entire face had exploded today.
"So before you say, from the comfort of your home, that we're exaggerating, please consider the injuries some have suffered [sic]."
She also advised those heading to the marches to bring medical supplies, including bandages, medical tape and eye pads.
Youngblud was seen pressing gauze against an injured man's brow.
Halsey praised her ex for stepping to help as things got out of hand yesterday.
She tweeted: "And a big personal thank you to @yungblud who literally ran exposed in front of rounds being shot to drag wounded people to safety without even thinking twice."
