Julian Lennon broke a long-held vow to never perform his father’s most iconic solo song, “Imagine,” at a concert for Ukrainian refugees on Saturday.

“Today, for the first time ever, I publicly performed my Dad’s song, ‘Imagine’,” Lennon, 59, wrote on YouTube. “The song reflects the light at the end of the tunnel, that we are all hoping for.”

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As part of the Stand Up For Ukraine campaign, a global fund-raising effort televised from Warsaw, Poland, the singer-songwriter son of Beatle John Lennon performed a cover rendition of his father’s anthem to peace.

“I had always said, that the only time I would ever consider singing ‘Imagine’ would be if it was the ‘End of the World’,” Lennon wrote.

“The War on Ukraine is an unimaginable tragedy,” he added. “As a human, and as an artist, I felt compelled to respond in the most significant way I could.”

The melancholy video clip featured Lennon singing surrounded by candles, in cadences eerily similar to his father’s, accompanied by acoustic guitarist Nuno Bettencourt.

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The performance concluded a broadcast European Union pledge drive that garnered $10.1 billion in public, private, and corporate funds for refugee aid.

Lennon is not the only musician to make news by performing songs in support of Ukraine.

Pink Floyd – minus Roger Waters – released “Hey Hey Rise Up,” its first original song in 28 years, at midnight Friday for the UN’s Ukraine Humanitarian Fund.

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David Gilmour, the guitarist and singer, told the Guardian that he was inspired by Ukrainian musician Andriy Khlyvnyuk, who quit his band BoomBox’s US tour to fight in Ukraine.

Gilmour was moved to act after seeing an Instagram video of the musician dressed in military uniform singing a protest song in Kyiv’s Sofiyskaya Square.

“I thought: that is pretty magical and maybe I can do something with this,” Gilmour said. “I’ve got a big platform that [Pink Floyd] have worked on for all these years. It’s a really difficult and frustrating thing to see this extraordinarily crazy, unjust attack by a major power on an independent, peaceful, democratic nation.”