He made headlines this week after allegedly attacking a photographer -- but Justin Bieber came off second best when he took on a glass wall.

The Canadian 18-year-old was out cold for 15 seconds, telling TMZ on Thursday he walked into the see-through barrier backstage between songs during a secret show in Paris.

Bieber said he was disorientated by the incident and walked back to his dressing room where he briefly passed out, but later resumed his performance and completed his set. Doctors reportedly confirmed Bieber had suffered concussion, but will recover.

"I'm fine. Just smacked my head and needed some water. All good," the pop idol tweeted shortly after the incident.

Making jokes about his glass wall collision, Bieber wrote later, "I will see u again Glass. I will have my revenge. BIEBER vs GLASS. MGM LAS VEGAS 2013. lol. #GottaLaughAtYourself."

Last Sunday a paparazzo in California claimed he was roughed up by Bieber when he tried to take a picture of the teen heartthrob. Police are investigating the allegation.

Bieber graduated from high school earlier in May and is due to release his third studio album in June. He has been riding the crest of worldwide fame since age 14, after his singing talents were discovered on YouTube.