Acting is of course so much more than merely playing pretend - great performances are often the result of actors extensively researching their part and doing whatever they can to get deeper into character.
This can be through obsessive method acting or simply receiving training in their character's given disciplines or habits.
Sometimes these skills and character traits can be a little on the uncommon side, though, requiring actors to take a crash course in something peculiarly specific.
These 10 actors, all of whom thoroughly convinced in their parts, were put through their paces with training and boot camps quite unlike anything you'd ever expect.
From learning how to speak in an animal's language to retraining their body to do things differently, adapting their own physicality, and even getting paid to get stoned for two weeks, these 10 actors dug deep into the specificity of their characters for maximum believability.
And the results speak for themselves on-screen - the performances thoroughly persuade as authentic, even if you'd probably never guess quite how obsessively the actors devoted themselves to perfecting a certain aspect of their character...
10. Sigourney Weaver Learned How To "Speak Gorilla" - Gorillas In The Mist
Sigourney Weaver received the second of her three Oscar nominations to date for her superb performance as slain naturalist Dian Fossey in Gorillas in the Mist, and it was certainly a well-earned nomination given the measures she undertook to convincingly perform opposite real gorillas.
First and foremost, Weaver worked with tropical field biologist and conservationist Ian Redmond, who trained her to not only understand gorillas' complex vocalisations but also perform them herself.
In effect, Weaver was taught to speak gorilla, allowing her to comprehend the subtleties of their spoken sounds and communicate with them in a rudimentary way.
Though some sequences were filmed using people in gorilla suits for reasons of practicality and safety for all involved, this training nevertheless allowed Weaver to completely convince as someone who dedicated their life, in the most ultimate sense, to the conservation of the mountain gorilla.