Michael Bublé and Late Late Show host James Corden teamed up in an emotional episode of Carpool Karaoke released in association with Stand up to Cancer.
The video starts as an upbeat singalong with the two harmonising on hit songs such as 'Haven't Met You Yet' and 'It's a Beautiful Day', but takes an emotional turn as Bublé opens up about his young son's battle with cancer.
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The singer said the moment he and his wife found out the diagnosis, his "whole life ended".
"He was three," he said, wiping away tears. "They sat us down and said it wasn't great, and so we just took it day by day."
"When all this started, I became the strength to somehow pull us and lift us and to be positive.
"When they got [the cancer] out and the chemo was done and they said, 'We did it, he's good, he's okay,' I fell. I just fell. My wife picks me up now."
Bublé encouraged viewers to donate to Stand Up to Cancer, saying "all of us can completely, completely make that huge difference".
"If you do it and you save just one little person, that's it. That's what life is, that's all that this is - simple."