beiber-sadface-230.jpgJustin Bieber has canceled one of his two upcoming concerts at Pavilhao Atlantico in Lisbon, Portugal "due to unforeseen circumstances."

A rep for the venue released the statement on Sunday and added, "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."

From showing up late to collapsing at his London concert at the O2 Arena, it seems like Bieber has had nothing but bad luck on the European leg of his tour.

Last week the 19-year-old singer got into a scuffle with a photographer in London, and prior to that he went on a rant about rumors and haters, and how no one should have a problem with him being shirtless. Huh?

Sounds like this little pop tart is getting a little burnt out ... maybe he needs a break?