Justin Bieber throws up on stage during 'Believe' tour opener

justin-bieber-throws-up-on-stage-gi.jpg Justin Bieber played the sold-out first show of his "Believe" tour Saturday night (Sept. 29), and fans got a little something extra as well -- though probably not what Bieber was hoping to give them.

The 18-year-old pop star vomited on stage midway through his set in Phoenix. As you can see in the video below, during his performance of "Out of Town Girl," he turns away from the crowd, doubles over and lets fly before running off stage.

He returned a few minutes later but then had to leave the stage again during "Beauty and a Beat," USA Today reports. The show stopped completely for a few minutes until he returned and confessed his illness.

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"Will you love me even though I'm throwing up on stage?" he asked the crowd, which of course responded in the affirmative. He then finished the show without a hitch, dedicating the song "One Less Lonely Girl" to Avalanna Routh, the 6-year-old "Mrs. Bieber" who died of a rare form of cancer earlier this week.

The culprit in Bieber's unplanned stomach pyrotechnics was apparently too much milk before the show. On Twitter after the concert, he posted a picture with the words "Great show. Getting better for tomorrow's show!!!! Love u" and followed up with "And ... milk was a bad choice. Lol."

Take a look at the video of Bieber throwing up on stage.

Photo/Video credit: Getty Images