Julian Lennon had long said that he would only sing “Imagine” if it were the end of the world.

But the war in Ukraine changed his thinking.

“The War on Ukraine is an unimaginable tragedy. … As a human, and as an artist, I felt compelled to respond in the most significant way I could,” Lennon writes on his YouTube channel about performing his father John’s 1971 classic song publicly for the first time, accompanied by guitarist Nuno Bettencourt.

He says the lyrics reflect a collective desire for peace worldwide, and “within this song, we’re transported to a space, where love and togetherness become our reality, if but for a moment in time.”

Lennon joined celebrities around the world calling on world leaders to do more to support refugees in the Stand Up For Ukraine campaign.

Watch: Julian Performs ‘Imagine’ for the Ukrainian People