(Source: Pinterest/Karen Neuman via Tumblr)
2. Clark Gable
Is that a young George Clooney? Nope! It's actually Clark Gable in the 1930s. The resemblance between the two is truly uncanny, although Gable died a year before Clooney was born. William Clark Gable was incomparable in his time; he was even referred to as "The King of Hollywood" or "The King," with leading roles in more than 60 classic Hollywood-era films. 

Photo found here.