There are over eight billion people in the world, and only so many ways a human being can look. There's bound to be some overlap. This holds true for celebrities too, and figuring out who that one actor or singer looks like is one of everyone's favorite game. Well, we'll help you play it, but with a new twist. Here are 20 celebrities that look exactly like someone else... from a different generation. 

Some doppelgängers wound up with similar roles in life; both Clark Gable and George Clooney are the leading men of their generation. But others, like Justin Timberlake and a mugshot of an unknown man from history, couldn't be more different. Chuck Norris and Vincent Van Gogh are my personal favorite pairing of mine. Is it just because they're both ginger-bearded men? Possibly, but they both had talented hands; one with the fist, and the other with the fingers. 

Here are 20 celebrities and their lookalikes from the past.