Justin Bieber brought his career full circle at the Atlanta stop of Purpose World Tour on Wednesday night (April 13): He invited Usher onstage for a surprise duet of the singer's 2001 hit “U Got It Bad."

Bieber launched into his own acoustic cover of the track for a few seconds before halting the performance, searching the stage with unfocused eyes. Sensing he may need some help, Usher stepped out and embraced Bieber before joining him in sonic harmony.

And that's not all! Joint Bieber and Usher fans were in for a real treat, because the pair also performed "I Don't Mind" and "U Don't Have to Call" together, though they sadly failed to sing the remixed version of Bieber's "Somebody to Love," which features Usher on its second verse.

For those of you unfamiliar with Bieber’s musical origins -- and therefore unaware of the significance of a Bieber/Usher duet -- know this: It was Usher who plucked the “Sorry” singer from obscurity and into the enduring spotlight.

Okay, technically, Scooter Braun did the true heavy lifting here and made the actual discovery via YouTube, but Usher gets a fair amount of credit for using his celebrity pull to promote Bieber as the second coming of Michael Jackson.

That comparison turned out to be true in some ways (the overzealous fans, the relentless media exposure), if inaccurate in others. By bringing Usher onstage, Bieber honored his beginnings.

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