25 Things You Didn't Know About Alien
8. The Cast Thought John Hurt Was Really Dying During The Chestburster Scene
The chestburster scene is infamous for the cast being largely in the dark about just what was going to happen to Kane, and their horrified reactions are entirely genuine. However, earlier in the scene, the actors genuinely feared for John Hurt's life.
When the Nostromo crew sit down to eat in the mess hall, Kane begins choking and then convulsing violently, and the others fly into a panic. Sigourney Weaver stated in an interview that his performance came on so naturally that she and the other cast members genuinely thought he had choked or was having a violent allergic reaction and may have been about to die in front of them.