Justin Bieber: Smokin' Like a Chimney at Kendall's Party

Justin Bieber took multiple smoke breaks at Kendall Jenner's birthday party ... maybe to celebrate his new-found freedom.

Justin was inside The Nice Guy but had to leave several times to light up. It's pretty clearly plain ol' tobacco, but we've never seen him smoke this way before.

As we reported, as of Monday, Justin's off formal probation in the egging case, so maybe a celebration ritual?