Catherine Powell“10,000 Hours,” the new song from Justin Bieber and Dan + Shay, had its live performance debut in an unusual setting: Dan + Shay sang it at Justin Bieber’s recent wedding celebration.  And as they tell Entertainment Tonight, they had no idea they were going to do it.

“We had never rehearsed it,” Dan Smyers tells ET. We obviously recorded it in the studio, but we never played it live in front of actual human beings. [But] Justin was like, ‘Sing ‘10,000 hours,’ we’re like, ‘OK, we’ll try.’ “

Shay Mooney jokes that he and Dan were just “making up the words,” but Dan adds, “It was good though, it was really fun and people were out on the dance floor rocking.”

“It’s awesome to get to attend their wedding and it was a blast,” Dan notes. “It was a really good time.”

As for the collaboration, it came about because Justin and Dan + Shay are both managed by Scooter Braun, who put the duo in touch with Justin.

“We’ve always wanted to do some collaboration with [Justin] and we wrote the song and thought it would be perfect and sent it over to him not knowing what would happen,” says Shay. “He loved the song; he’s in a similar place in his life, just got married, and so it was really cool to have that moment all together.”

“The timing of it worked out and we still can’t believe that it happened,” he adds. “I’m waiting to wake up tomorrow and [find out] like, ‘That actually never happened to you guys.’”

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