NEW YORK -- Justin Bieber tweets that he's "fine" after suffering what doctors say was a mild concussion after he ran into a glass wall backstage at a concert in Paris.
Bieber told TMZ.com that he was disoriented, but went on with the concert.
TMZ says Bieber later passed out as he was walking to his dressing room. His manager tweets that Bieber's "a trooper" and a "tough kid."
This isn't Bieber's first encounter with glass (see video below). He ran into a revolving door in 2010. Referring to that and his recent accident, Bieber tweeted a message to "glass" saying he'll have his revenge.