Christian Bale

If you watch The Machinist and then Batman Begins in one sitting you might be forgiven for thinking that Christian Bale - lead actor in both - is two different people.

Bale plays an anorexic insomniac in the first, and the world’s greatest superhero in the second. The films were shot within five months of each other, with Bale putting on about 100 pounds in that time. Experts suggest his routine was based on martial arts circuit training - Batman is, after all, a great fighter - interspersed with compound weight bearing exercises.

They all agree that Bale’s transformation from super skinny to uber ripped would have taken a lot of hard work.