One of the most memorable scenes where mob boss Don Vito Corleone delivers brutal orders while stroking a cat wasn't scripted to involve a pet. The cute kitten somehow wound up on the set and ended up on actor's lap during shooting helping to create an iconic scene.

While the safest choice for a scene like that is to use special effects and make-up, Steve Carell thought that it would be much better if the waxing was real. The reaction the character is having is completely genuine. Carell said that his experience was so horrible that he promised to never do that for a movie ever again.

The movie had a small budget so most of the people you see in the background are not extras, they are regular people who had no idea they were being filmed. So the scene where Rocky runs through a market and a man throws him an orange was completely unscripted.

While it's hard to imagine Jim Gordon's promotion scene without the Joker clapping sarcastically, this scene was never in the script. It is a work of Heath Ledger’s excellent improvisation.

During the scene where Eowyn stares into the distance, we can see a flag being ripped off a pole and flying away. While this scene may look intentional and metaphorical, the flag flew away by accident but it fit so well with the scene, that it was kept in the final cut.

The scene where Mrs. Doubtfire had to cover her face with icing didn't go as planned. When the icing started dripping down the actor's face because the heat from set lights made it melt, Robbie Williams had to improvise. At the moment when the icing dripped into Mrs. Sellner’s tea, he decided to say, “There you go, you’ve got your cream and your sugar now.”

The moment when Peter drops the orb was not scripted. The clumsy actor Chris Pratt accidentally dropped it but quickly picked the orb up. Since Chris didn't break character and the scene looked good it stayed in the film.

The scene where Indiana Jones meets a warrior armed with a sword was scripted to be an intense duel. However, the actor Harrison Ford was ill from food poisoning and didn't have the strength to perform, so the director made a small change - instead of dueling, Indiana pulls out the revolver and shoots the villain. The scene became one of the most iconic moments in movie history.

The scene where Thor hangs his hammer on a coat rack was so good that everyone probably thought it was scripted, however, it was not. Chris Hemsworth was just trying to be funny but his improvisation was so good, the scene was put into the final cut.

In the scene, when Princess Leia tells Han Solo that she loves him, he was supposed to respond by saying "I love you too". However, Harrison Ford felt that this response wasn't suitable for his character, so instead, he improvised and responded by saying "I know".

The line "My name’s Forrest Gump. People call me Forrest Gump" wasn't scripted, Tom Hanks said the last bit by accident.

In this film, Anne Hathaway portrayed an awkward and geeky girl who finds out she's heir apparent to the throne of Genovia. While filming a scene where the character was supposed to walk on bleachers with her friend, Anne took a pretty nasty tumble. However, it fitted so well with the clumsy character that this unscripted accident was left in the film.

The director could not stop Robert Downey Jr. from sneaking snacks into the set, so he had no other choice but to make his snacking habit a part of his character. So all the scenes of Tony Stark eating are probably not scripted.

Leonardo DiCaprio is an excellent actor who doesn't break character even when he hurts himself. He proved that during an intense scene when he hurt his arm with a shard of glass and blood started gushing from his wound. This scene wasn't scripted and the blood was real, it was left in the final cut because of the amazing acting.

In this movie, Anthony Hopkins only had 25 minutes of screen time, however, it was enough time for him to create one of the most chilling performances of all time. One of the most iconic scenes was when Dr. Hannibal Lecter is talking about his crimes with an FBI agent and starts to hiss. It was completely improvised and the reaction on Foster's face is genuine.

The famous line "I am the king of the world" wasn't scripted, it was made up on the spot by the director. After trying several different lines, James Cameron realized that nothing was working and told Leo to just say "I am the king of the world" and really sell it. This scene became probably the most iconic part of the movie.

The line-up scene where we see characters laughing was supposed to be a serious one. The director was angry at the actors for cracking up, but they said they couldn't keep a straight face on because one of them was farting during filming.

During the scene where a character played by Kate Winslet disappears, the look on Jim Carrey's face is genuine. He wasn't told that Kate will disappear, so he was really trying to find her.

R. Lee Ermey, who played Gny. Sgt. Hartman, was a real-life Parris Island Marine drill instructor during the war. At first, he was hired as a technical adviser but later was given a part in the film and improvised all training scenes himself.

The scene in Dirty Dancing where Johnny and Baby are crawling towards each other on the floor wasn't scripted. They were just warming up before filming, but the director loved it, so it was kept in the film.

While filming, Dustin Hoffman accidentally passed gas, however, he and Tom Cruise made it look like it was part of the scene. Actors managed to stay in character and spontaneously created such a good scene that it became a fan favorite.

Al Pacino prepared for his part by not allowing his eyes to focus on anything. He got so good at simulating blindness, that he could barely see anything. The scene on the street, where the actor fell over a garbage can, happened by accident because of his bad vision.

Do you remember one of the funniest scenes in the movie, when Roman said "Hey Mia, You better hide your baby oil" and Hobbs responded with "You better hide that big ass forehead"? Well, actor Dwayne Johnson came up with this comeback on the spot because in the script his character wasn't supposed to respond at all.

The scene where actor Daryl Hannah runs away panicking, but along the way slips and shatters a window of the van with her elbow looks completely scripted, however, it was an accident. Turns out Hannah slipped accidentally and was taken to the hospital because she broke her elbow.

It's probably not so surprising that cringy scene in which Matthew McConaughey is banging his chest wasn't in the script. Matthew revealed that he was doing it before each take as a relaxation technique. Leonardo DiCaprio suggested using in the scene and it fit perfectly.

The famous scene where Nick the Greek breaks the coffee table with a juice glass wasn't scripted. In fact, it was an accident and the shocked look on the actor’s face is genuine.

The line “Ah... Houston, we have a problem” which Matthew Lillard says in the scene where his character Stuart realizes that the gun is missing was improvised and not scripted.

The scene where Tom Hanks picks up the gurney himself and throws it into the ambulance wasn't scripted, he thought of doing it that on the spot.

The epic plate throwing scene in this movie was improvised. In the script, Lester Burnham throws the plate at the floor, however, Kevin Spacey decided to violently throw it into the wall right behind Thora Birch's back, landing genuine reactions from the actors in the scene.

Remember the scene where Terry says that if he were a lion and Allen were tuna, he would swim into the ocean and eat Allen? Well according to the script, Aleen wasn't supposed to respond, but the actor decided to improvise by explaining why a swimming lion is a stupid idea.