Nobody "becomes" a character. You can't act unless you are who you are.

Related:

• An actor's a guy who if you ain't talkin' about him,
  ain't listening. -- Marlon...
• You boys lookin' for trouble?" "Sure.Whaddya got?" -
  Marlon Brando, "The Wild...
• How many American standup comedians -- does it take to change a light bulb?
  You know what bugs me about light bulbs? The other...
• Never get angry, never make a threat. Reason with people.
  Marlon Brando (in The Godfather, screenplay by Mario...
• Nobody can give you
  freedom...
• A Streetcar Named Desire Stel-la! -
  Marlon...
• Do nothing unless you must, and when you must act -
  hesitate...
• Character is who you are in the dark. --
  Lord John...