And although the pop star is now out and about—he was discharged from the hospital and is still slated to perform his final London show tonight—footage has emerged showing him buckling onstage during the concert in question, underscoring the considerable alarm that the incident raised among both his entourage and his fans.
In the clip, the 19-year-old prances onstage while performing "Beauty and a Beat" when suddenly, he appears light-headed and stops to catch his breath while a vocal track continues to play.
He then bends down, propping himself up against his knees before later stumbling toward the back of the stage.
Bieber was subsequently administered oxygen backstage, but after a 10-minute hiatus, he returned onstage to finish the show, flouting doctors' orders that he rest up and pull the plug on the concert.
The crooner, however, seemed to be having a rough time getting back on track: On Friday morning, an agitated Bieber was photographed lunging at paparazzi while being restrained by his bodyguard, who at one point lifted the pop star off the ground.
Bieber later alluded to the incident on Twitter.
He also promised to channel his energy into mounting a good show Friday night.
"Gonna get focused on this show tonight. Adrenaline is high now. Gonna put it on the stage," he wrote.