Julian Lennon broke his longstanding vow never to perform his father’s most iconic solo song, “Imagine,” during a benefit for Ukrainian refugees 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.”

The singer-songwriter son of Beatle John Lennon presented the cover version of his father’s ode to peace as part of the Stand Up For Ukraine campaign, a global fund-raising effort broadcast from Warsaw, Poland.

“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.

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