In the world of Hollywood, actors are willing to go to extreme lengths for their art and not just rely on help from a make-up artist and/or Photoshop to do the job.
Christian Bale- The Machinist
One of the most dramatic transformations of all time was Christian Bale's severe weight-loss for 2004's The Machinist. He lost over 27kg to play insomniac Trevor Reznik.
The actor played a man whose health deteriorates after not being able to sleep for a year. His daily diet consisted of coffee, cigarettes and an apple.