10 Hot Celebrities Who've Played Twins or Doppelgangers (PHOTOS)

They may look almost completely identical, but The Vampire Diaries’ Katherine Pierce (left) and Elena Gilbert (right) — both played by Nina Dobrev — couldn’t be more different. Katherine is a centuries-old vampire: sexy, confident, and conniving to the core. Elena is her much-younger human (well, used-to-be human) look-alike, and her polar opposite in every way: sweet, genuine, kind, and fiercely loyal to her friends and family. Both women are Petrova doppelgangers, descendants of an ancient line whose blood is literally the key to unlocking a vampire and werewolf curse.