Justin Bieber is having the worst birthday week ever.
During a concert at London's O2 arena Thursday, the Biebs experienced difficulty breathing and was transported to a local doctor-- but not before the 19-year-old insisted on finishing the last portion of his show.
"Justin got very light of breath," said the pop star's manager, Scooter Braun, to the concerned crowd as Justin was administered oxygen by an on-site EMT backstage.
After 20 minutes of rest, Justin returned to finish his set.
"Getting better. thanks for everyone pulling me thru tonight," tweeted Justin after wrapping the concert. "best fans in the world. figuring out what happened. thanks for the love." He also updated his fans on Instagram by posting a shirtless photo of himself in the hospital with the caption, "Gettin better listening to Janice Joplin."
ET spoke with the singer's rep, who confirmed the star had been taken to the doctor and is currently awaiting test results.
Earlier this week, Justin issued a public apology for upsetting his London fans when he showed up nearly two hours late to a concert.
Star Sightings: Celebrity Candids
Are These Celebs Too Tan?! Cast Your Vote!