With regular ad-libbing and improvisation as well as genuine mistakes being frequent occurrences on film sets, it's not surprising that some of the best-loved movie moments from cinema history almost never happened.
From Jack Nicholson's "Here's Johnny!" to DiCaprio's cut hand, here are 10 of the most iconic unscripted moments in cinema history.
1. DiCaprio Cuts His Hand for Real in Django Unchained (2012)
While giving a speech over dinner, Calvin Candie (Leo DiCaprio) unexpectedly erupts into a foul-mouthed tirade and slams his hand on the table causing blood to visibly trickle down his hand. This was a genuine accident on the set but Tarantino continued to film as DiCaprio never broke character. He received a standing ovation from the cast and crew once the scene was over.
2. The Most Annoying Sound in the World in Dumb & Dumber (1994)
Lloyd (Jim Carrey) and Harry (Jeff Daniels) pick up a hitchhiker (actually a hitman) and proceed to engage in some childish antics culminating in Lloyd enlightening the hitman on what the most annoying sound in the world sounds like. Jim Carrey's improvisation provides an incredibly funny moment, made even better by the quick glimpse of Jeff Daniels cracking up before the camera cuts away.
3. The Joker Looks Bemused as the Hospital Explodes in The Dark Knight (2008)
Heath Ledger's turn as Batman's deadliest foe earned the late actor a posthumous Oscar. One of his most memorable scenes is when he is leaving the hospital dressed as a nurse. He looks back and forth between the hospital and the remote detonator in his hand expressing confusion before it eventually blows up; an aspect improvised when the timed explosions were delayed without Ledger's knowledge.
4. "You Hear That?" in Reservoir Dogs (1992)
Mr. Blonde (Michael Madsen) cuts off the ear of the cop they've got tied up in the warehouse, proceeding to then speak into the organ: "Hey what's going on? You hear that?" before laughing to himself. Tarantino had nothing scripted for Madsen to do once the ear was off, so he improvised this darkly comic moment of dialogue, heightening the impact of an already disturbing scene.
5. "Here's Johnny!" in The Shining (1980)
In one of The Shining's most iconic scenes, Jack (Jack Nicholson) begins chopping through a door with an axe before sticking his head through and proclaiming "Here's Johnny!". Nicholson had tried other lines but nothing seemed to fit. He eventually decided on this line in reference to a popular catchphrase of the time - the intro to The Johnny Carson Show.
6. Hannibal Lecter's Hiss in The Silence of The Lambs (1991)
The infamous 'f-f-f-f' noise Lecter makes at the end of his 'liver and Chianti' story was in fact made up by Anthony Hopkins during a rehearsal. Director Jonathan Demme liked it so much it stayed and it went on to become one of the film's most infamous scenes. Anthony Hopkins would go on to earn an Academy Award despite having less than 25 minutes of screen time.
7. "Mein Fuhrer, I Can Walk" in Dr. Strangelove (1964)
Peter Sellers improvised so many of his lines, he was credited as a co-writer. One standout moment comes near the film's climax. While in character as the wheelchair-bound Dr. Strangelove, Sellers stands up before uttering the line "Mein Fuhrer, I can walk". He had momentarily forgotten that his character was supposed to be disabled.
8. "I Love You", "I Know" in The Empire Strikes Back (1980)
Seconds before being frozen in carbonite, Han Solo responds to Princess Leia's declaration of love with the slightly cocky response "I know". It's pretty badass but it was never in the script. The original line was supposed to be "I love you too" but Harrison Ford didn't think it fit and so changed it. It has since become one of the franchise's most quoted lines.
9. Robin Williams' fart story in Good Will Hunting (1997)
Will (Matt Damon) is at one of his therapy sessions when his therapist Sean Maguire (Robin Williams) tells him a story of his wife and her farting habit. This whole scene was made up by Williams on the spot and Damon's laughing is completely genuine. If you look closely, you can even spot the camera shaking due to the cameraman laughing as well.
10. Indiana Jones Shoots a Would-Be Assailant in Raiders of the Lost Ark (1981)
You know this one already, right? This scene was originally intended to be a full-on sword fight. However, Harrison Ford was reported to have been struck with food poisoning and didn't feel up to swishing a sword around. Ford made the suggestion to Spielberg to just take out a gun and "shoot the sucker" which Spielberg loved. The result is one of the film's most memorable laugh-out-loud moments.
From: Digital Spy