JUSTIN BIEBER PLAYS BEER PONG


photo:  tmz...duh!

TMZ has posted a picture of a kid who appears to be Justin Bieber playing BEER PONG!!!! 

A "source" says this game took place in either Canada or Georgia.  But it was last year, when Justin was 17....so even if it was in Canada, it's still ILLEGAL!  The "source" says Justin DID drink. 

Another "source" says the game went down in Alabama in June. 

No matter what you think, our question is....WHY is Justin wearing a backpack?  That seems a bit strange.