Justin Bieber proved last night that the slogan, “Milk Does A Body Good” may not always apply to his body. At least not before a show.

The 18-year-old singer learned the hard way not to drink the white liquid before a concert because he had a horrible accident after he did just that before kicking off his “Believe” tour in Glendale, Ariz., Saturday night. 

Bieber was in the thick of performing “Out of Town Girl” when he suddenly turned his back to the audience, and threw up on stage. Twice. He then did what we all would have, he ran off stage only to come back quickly and apologize.

“I’m sorry, I’m going to slow things down,” Bieber said and then performed the ballad “Fall” on an acoustic guitar.

Things looked cool until they weren’t again. Bieber had to run off stage again in the middle of singing “Beauty and a Beat.”

“It’s hard for me, you know, not feeling great and throwing up in front of a bunch of people,” Bieber said when he returned to his fans. “Will you love me even though I’m throwing up on stage? OK, I wanted to give you my best show ever, so do you mind if I finish it?”

Of course his fans forgave him instantly. And at least Bieber has a good sense of humor about things. The Biebs Tweeted the photo of himself in bed after the show with the caption, “Great show. Getting better for tomorrow’s show!!!! Love u.” Oh, and then he said, “And …. Milk was a bad choice! Lol. Goodnight Avalanna. Tonight was for u. I love u.”

Watch Justin Bieber throw up in the YouTube video below:

http://youtu.be/KY3tLA544r4