Justin Bieber performs at 02 Arena on March 5, 2013 in London. Credit: Chiaki Nozu/WireImage

Justin Bieber has canceled one of his two scheduled concerts in Lisbon, Portugal, Us Weekly has learned. The venue made the announcement on Sunday, March 10.

"Due to unforeseen circumstances we have been forced to cancel the show scheduled for March 12," a rep for the Pavilhao Atlantico said in a statement. "Justin looks forward to playing for his Portuguese fans on March 11. Refunds for ticket holders on March 12 are available from point of purchase."

On Thursday, March 7, the 19-year-old singer fainted midway through his concert in London. "He left the stage for 20 minutes, then came back and finished the show," Bieber's rep told Us. The "Beauty and the Beat" singer soldiered through his March 8 performance at the O2 Arena despite feeling "a little short of breath."

Though the cause of his fainting spell has not been revealed, Bieber appears to be in better health. "Slept good last night," he tweeted March 10. "Hanging with the boys today."