The greatest acting in the world is about much more than just speaking your lines and conveying the right emotions: you have to convince the audience that you truly belong within the world of the film, that you truly are your character.
Raw talent can help you accomplish that task, sure, but we've also seen actors do other things like pack on muscle, shed fat, or speak in a completely different dialect, just to juice up their performances and give them that extra bit of authenticity.
Something else that many stars like to do while prepping for a role is learn a brand-new skill, and while these are often quite "basic" and are quite common for actors to learn - such as riding a horse, shooting a gun, or playing an instrument - some acquire abilities that are a lot more unusual or a lot more unique.
While a lot of these actors could've got away with not going that extra mile, they went out of their way to pick up some pretty insane skills, and their performances - and their movies as a whole - undoubtedly benefited from that decision.
10. Tom Cruise Learned How To Hold His Breath For Six Minutes (Mission Impossible: Rogue Nation)
Over the last decade, the build-up to each new Mission Impossible movie has become all about guessing what crazy, life-threatening stunt Tom Cruise will perform next.
Scaling skyscrapers, flying helicopters, HALO jumping, riding a motorcycle through oncoming traffic - he's done it all, and while all that huge stuff is undeniably impressive, one of the most underrated skills Cruise has picked up over the years is one he had to learn for the fifth instalment in the franchise, Rogue Nation.
For a lengthy underwater sequence midway through the film, Cruise worked with a freediving record holder so he could, essentially, teach himself how to not breathe.
The scene took two months to prepare for, and although Cruise "blacked out" a couple of times along the way, he got so proficient at his breathing exercises that he was eventually able to hold his breath for a staggering six minutes.
Cruise's determination to deliver great action sequences should be commended, and the results speak for themselves. Also, as an added bonus, he'll now be able to survive longer than your average human if he ever finds himself stranded in open water.