Sony

Given that acting is all about becoming another person - so well, in fact, that your goal is to convince audiences that you really are them time and time again - it's no wonder that there are several schools of thought with regards to how one might approach such a complicated task. Whereas some actors choose to simply turn up on the set of their latest movie, take a deep breath and immerse themselves in their characters on a whim, there are others actors who find it's much easier to immerse themselves into a role if they go utterly insane.

This occurs in the research stages, of course, when an actor has signed on to star in a movie and is given a few months before shooting begins. For some, this period might be used to see friends and family, party, relax, or regret signing on to do anything, though for other, more seriously-inclined performers, this build-up is considered to be the most important part of the entire process.

Just as in the case of a novelist, good writing always goes back to the research. But how far is too far?

Here are 10 actors who conducted some seriously insane levels of research prior to starring in some of their most iconic movie roles...