Justin Bieber Greases Up His Look Backstage

Justin Bieber is putting aside his super saggy pants in favor of something a little tighter.

The 18-year-old teen sensation was channeling his inner bad boy with a look only Danny Zuko from Grease would love.

Biebs posted the above photo and the following: "To those of u who tell me not to sag my pants. Double think that."

Perhaps Biebs will shave his head this summer. We'd love to see that!