10 Genius Techniques Directors Used To Get Great Movie Performances

6. Ridley Scott Didn't Tell The Cast About The Chestburster - Alien

Ridley Scott's sci-fi masterpiece Alien is jam-packed with iconic and unforgettable scenes, but none more so than the terrifying screen debut of the Xenomorph, which bursts out of Kane's (John Hurt) chest and scuttles away, much to the crew's horror.

In a masterstroke from Scott, he decided not to prep the cast on exactly what they would be seeing. They knew the alien would reveal itself, but the specifics - namely the spurting blood - were kept out of the script.

As such, the thoroughly freaked-out reactions from the cast - especially a beside-herself Veronica Cartwright - are completely genuine, and absolutely enhance the intensity of the scene.

Scott said of his decision to ambush his cast in this way, "The reactions were going to be the most difficult thing. If an actor is just acting terrified, you can't get the genuine look of raw, animal fear."

Hilariously, Weaver said, "Everyone was wearing raincoats - we should have been a little suspicious. And, oh God, the smell. It was just awful...All I could think of was John, frankly. I wasn't even thinking that we were making a movie."

Nobody received permanent psychological scars (probably) and the result is one of the most intensely unsettling scenes in cinema history, so this was clearly a win-win.