Actors are paid millions of dollars to express complex human emotions. But no matter how good the actor, sometimes a script just doesn't offer the spontaneity of real life.
Those who say actors have it easy, read on. From exploding aliens to full on lashings, these surprising scenes show genuine reactions from leading stars.
With this in mind, lets take a look at numerous clips where sadistic directors will do anything to get the raw emotion they so desperately crave.
1. 'Alien' (1979) - Chestbursting Surprise
The iconic scene of creepy cock shaped alien bursting through John Hurts chest and emerging into this world like a giant worm on acid is one of the most memorable in cinema. It's certainly shocking to watch on first viewing.
Imagine BEING there. Ridley Scott didn't tell any of the cast (other than hostess with the mostchest John Hurt) what was about to happen, in order to capture a genuine sense of fear. And that he did. When the creature rudely thrusts itself through Kane's sternum, the reactions you see are real. So real in fact, that Veronica Cartwright actually fainted and the scene had to be completed the next day. Oops.
2. 'Exorcist' (1973) - That's a Bit Sick
Being on the receiving end of copious amounts of chunder thunder can't be the highlight of your acting career. The director told Jason Miller than the demonic, neck twisting child would puke all over his chest. Bad enough. However what he didn't say was that the pump mechanism was secretly changed to pump green spew (aka pea soup) all over his face. Nice.
3. 'Willy Wonka & the Chocolate Factory' (1971) - Scaring Children
In what would be a decent case for a child cruelty lawsuit, during the filming of Willy Wonka none of the children were told of the events that would occur, for the entire length of the movie.
So, all those reactions you lauded the children for good acting were actually genuine wonder and animalistic fear and confusion. Willy Wonka... What a w-w-w-... well respected fellow.
4. 'Glory' (1989) - Denzel Gets Lashed
In this film Civil War film, Denzel Washington plays a slave who has volunteered to fight in the union army.
One of the most gripping and difficult to watch scenes occurs when Private Silas Trip (Washington) is flogged due to disobeying his superior, which strikes deeper due to his bare flesh already being rife with scars from lashings he had received earlier.
In the scene, director Edward Zwick told the person off camera who was whipping the Training Day actor to keep whipping, much more than Denzel was expecting. The harrowing close up shot of his reaction is genuine.
5. 'Rocky IV' (1985) - A Sucker-Punch for Stallone
During many infamous boxing bouts throughout the Rocky franchise, the level of realism is through the roof. We feel every punch as if we were in the ring with Sly himself.
Part of the reasons for that is due to people, well, punching each other for real. In one particular scene, Stallone goaded Dolph Lundgren to punch him has hard as he could in the chest. The result? A nine day hospital stint. Error mate.
6. 'Fight Club' (1999) - Norton Smacks Pitt For Real
To bridge the gap between normality and, well, beating the living shit out of each other, Fight Club required a pivotal scene where Ed Norton's character feels the buzz of aggression for the first time.
In the parking lot, Tyler Durden asks "the narrator" (we all know who he is really) to punch him as hard as he can. The Narrator duly obliges. However, what we don't know off screen is that the initial direction was actually for Norton to punch Pitt in the chest.
When David Fincher told him to punch Pitt in the head, he initially had reservations, especially because the lead actors had only just met for the first time. Like a true pro, Pitt remained flawlessly in character. Note Norton's sly, knowing smile after he connects, too.
7. 'Pirates of the Caribbean: Dead Man's Chest' (2006) A Hidden Surprise
Because I'm a nice guy, I'm giving you lovely people a spoiler warning for this one. Just for those who haven't caught one of the highest grossing movies of all time in the near decade it's been released. WARNING. SPOILER.
In the final scene of the film, before the scene was shot, the rest of the cast were told that Anamaria, played by Zoe Saldana in Pirates of the Caribbean: The Curse of the Black Pearl, would be coming down the stars, NOT Captain Hector Barbossa.