Not even a hit on the head can dampen Justin Bieber's spirits, but maybe it's because he's used to it.
After pulling his hip earlier in the week, the 18-year-old "Boyfriend" singer suffered a concussion Thursday after walking into a glass wall backstage in Paris -- and this wasn't the first time he has had such an accident.
You may remember seeing Bieber smacking his head on a revolving door in May 2010. That time, the incident was caught on camera.
Unfortunately for Bieber, he had another run-in (literally) with a glass wall later that year.
In Thursday's incident, the Canadian pop star was knocked out for approximately 15 seconds after he rammed into glass backstage during one of his shows. But, like the "tough" Canadian he is, Bieber quickly returned to the stage to finish his set.
"I will see u again Glass. I will have my revenge. BIEBER vs GLASS. MGM LAS VEGAS 2013. lol. #GottaLaughAtYourself" he tweeted later.
"Yeah. so this will never be my house. lol," the Bieb tweeted early Friday morning, adding a picture of a glass house.
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