Michael Bublé and Stephen Colbert delivered an impromptu performance of a classic sea shanty on Wednesday’s  “The Late Show”.

Colbert asked the Canadian hitmaker about his time working as a commercial fisherman.

Bublé explained how from the age of 13 until he was 21 he worked on the same boat going back and forth in the summers to catch salmon between Vancouver Island and Alaska.

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Colbert said he was a fan of “Barrett’s Privateers” — a shanty about Canadian pirates — and asked a surprised Bublé to sing it with him.

The modern folk song was written and performed by Canadian musician Stan Rogers, who passed away on June 2, 1983.

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Despite not seeming too confident about the performance at the start, Bublé quickly got into it and tried to keep up with Colbert who knew every single lyric.

Elsewhere in the appearance, Bublé also revealed how his grandfather used to bribe nightclub owners to let him sing at age 16.

“The Late Show with Stephen Colbert” airs weeknights at 11:35 p.m. on Global.