Geneticists have no single answer to the question why the light appear similar to each other people, while experts believe that almost everyone has a double or twins. Not everyone can meet his "clone", maybe that's why it is assumed that only among celebrities meet up? In addition, there is a theory that similar people choose similar profession.
Natalie Portman and Keira Knightley
Heath Ledger and Joseph Gordon-Levitt
Josh Duhamel and Johnny Knoxville
Ralph Fiennes and Bradley Cooper
Johnny Depp and Skeet Ulrich
Jennifer Garner and Hilary Swank
Portia de Rossi and Drea de Matteo