Russian punk band Pornofilmy and Ukrainian pop-rockers Nervy are performing together on a charity tour entitled "Stand with Ukraine".
They say profits from the concerts, the latest of which took place in the Polish city of Gdansk on Wednesday, will be donated to organisations helping war-affected Ukrainians and used for the purchase of medical equipment.
The tour, which also features Russian rapper Face, was initiated by Nervy frontman Zhenya Milkovskyi, who was born in Pokrovsk, in Ukraine's Donetsk region, and had been living in Moscow since 2014 after signing with a Russian label.
"As soon as the war started, we immediately felt the urge to do something useful. And I think this is the most helpful thing we can do now," Milkovskyi told Reuters.
Milkovskyi was forced to leave Russia after making a series of posts on his social media networks condemning Moscow's Feb 24 invasion of Ukraine.
"I am now banned from entering (Russia) for 50 years. I'm Russia's enemy - don't know what it's really called - simply, an unwelcome person," he said.
Russia says it launched its "special military operation" to disarm and "denazify" its neighbour. Ukraine and its allies call the invasion an unprovoked war of aggression.
Russian band Pornofilmy have faced official hostility for their anti-war stance. The band's official page on Russian social network Vkontakte was blocked after a ruling by Russia's Prosecutor General's Office on Jun 2.
"Well, I think not all Russians support this war. I think many are afraid to set out their position, they assume nothing depends on them, and the system will chew them up and spit them out," said singer Volodia Kotliarov.
Russia's state pollster Public Opinion Research Centre says 72% of Russians support the Kremlin's actions in Ukraine.
Kotliarov said part of the band's motivation for joining the tour to help the victims of the war was the strong connection they had built with Ukrainian audiences.
"It seems to me that it was not us who came to this decision, but this decision has come to us," he said. "It was probably the only right thing to do in this situation."