Justin Bieber's concert in Arizona did not go as planned as he got sick on stage.

During his concert in Glendale, Arizona, he was singing, "Out of Town Girl" when he threw up on stage. He wrote on his twitter later, "Milk was a bad choice."

The video clip of this scene was funny because although Bieber got sick, the back dancers continued to dance the choreography, not caring at what was going on.

Bieber's album, Believe, has sold over 887,000 copies in the U.S.