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Of course, in true Bieber fashion -- the popstar is known for being quite the jokester -- the juicy tell-all appearance was all fun and games.
For example, Justin kicked off the list with "My new fragrance Someday also makes a delicious, low-calorie salad dressing." Self-promo and comedy all in one fell swoop. Nicely played, Biebs!
Check out Bieber hanging with Letterman and the full list of funny facts in the video below. For a list of real facts about the Biebz, check out our 17 Things You Didn't Know About Justin Bieber countdown.
Watch Justin Bieber on 'Letterman.'