Michael Bublé performs with a couple of Kiwis he found singing at the Auckland fish market

Popular crooner Michael Bublé was enjoying lunch with his family at Auckland's fish market on Sunday when he was struck by the acoustic duo performing.

Little did the singers know, their brush with Bublé would see them enter the spotlight later that night at his electric final show of the Higher tour at Auckland's Spark Arena.

Kiwis Vanessa Abernethy and Johnny Gordey – known as 2fold – perform at the fish markets once a month. They didn't recognise the singer at first.

Watch the video above.

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"The song that he really loved was (Joe Cocker and Jennifer Warnes' hit) Love Lift Us Up," 52-year-old Abernethy told Stuff.

"I thought 'Oh he obviously enjoys music,' because he was really energetic, and then he comes and sits down, and then he comes a bit closer and says to me, 'You've got an amazing voice'."

Even disguised with "a cap and sunnies on", Bublé's lush voice gave it away.

"I was just like, 'Are you Michael Bublé?!'" Abernethy said.

"I didn't say it into the mic, and he goes, 'Shhhh. You're a better singer than I am.' And I said, 'Well my bank account doesn't say that'.

"Then he said, 'Can you come and sing tonight?' and we were like, 'What?!'"

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After he had finished lunch with his wife, actress Luisana Lopilato, and their four children, Bublé approached the pair again to request that they really do come and sing with him later that night.

"He said, 'Do you mind if I just stop you for a minute? Can you give me your number and I'll get my agent to call you. Were you coming to the show tonight?'"

"And I said, 'Well no, I wasn't, but Johnny has tickets. I don't have any tickets.' And he says, 'Well I can definitely give you tickets, so if you guys come, why don't we do something tonight together?'

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"I was like, 'Is this like a prank call or something?!' It was surreal. It was really cool."

Just hours later, Abernethy and Gordey would be a highlight of Bublé's masterful show, singing the same song Love Lift Us Up along with him and the 12,000 strong audience.

Bublé introduced their cameo in his show by retelling the tale, saying of Abernethy's singing: "I was just sitting there eating my fish fingers and thinking, 'Oh my God, this voice."

This story originally appeared on Stuff and was republished with permission. Read the original here.