Michael Bublé says his family was shocked when they heard his singing voice for the first time.

The "Sway" singer recalled the moment while speaking with Willie Geist for the Oct. 26 episode of Sunday Sitdown. Bublé said one Christmas Eve when he was 13 years old, he was sitting in the back seat of his family's car driving back from his grandparents' house.

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"We were singing, I think it was 'I’m dreaming of a white Christmas/ with every Christmas card I write.' And then all of a sudden I went, 'May your days be merry and bright.' And it was, you know, the whole car going, 'What the hell?'" he said with a laugh.

Bublé then started to take singing more seriously. While singing at a wedding in 2000, he was discovered by record producer Davi

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