Improvisation is a sword most actors learn how to wield. However, only the ones who've mastered the art can come up with an absolutely killer line on the spot, often making for some of the most memorable movie moments.
3.When Princess Leia told Han Solo "I love you" in The Empire Strikes Back, Harrison Ford replied with "I know" because he thought it fit his character better than the scripted response.
4.Matthew McConaughey was thrown into a scene in Dazed and Confused last minute with no lines written, so as soon as the director called "Action!" he said, "Alright, alright, alright!”
5.Tony Stark originally wasn't supposed to reveal his superhero identity at the end of Iron Man, but at the last minute, Robert Downey Jr. added, "I am Iron Man."
7.While filming a fight scene in Fight Club, Edward Norton surprised Brad Pitt by hitting him in the ear, so Brad's response of "Why the ear?" was genuine.
8.During the last week of filming for Taxi Driver, director Martin Scorsese locked himself and Robert De Niro in a room and asked the actor to say something in the mirror, so Robert came up with, “You talkin’ to me?"
9.Shooting on Casablanca began with an unfinished script, so as Rick and Ilsa said their goodbyes, Humphrey Bogart ad-libbed the line "Here's looking at you, kid."
10.When Murray shaves his head during the party scene in Clueless, Donald Faison said, "I'm keeping it real!" because he heard a younger neighbor say it.
11.While filming the scene where Forrest meets Bubba in Forrest Gump, Tom Hanks came up with the line, "My name’s Forrest Gump. People call me Forrest Gump."
13.While filming Anchorman: The Legend of Ron Burgundy, director Adam McKay told Steve Carrell to just say anything because he wanted Brick Tamland to have more lines, so Steve said, “I love lamp.”
14.In Avengers: Infinity War, the line "I don't wanna go," which Peter Parker utters right before he turns to dust, was inspired by an acting technique Tom Holland uses to make himself cry.
15.In The Godfather, Clemenza's original line ended at "Leave the gun," but Richard Castellano added "take the cannoli" at the suggestion of his wife, Ardell Sheridan.
16.Joe Pesci's line "Funny how?" in Goodfellas was based on a real incident from when he was a server who accidentally offended a mobster by telling him he was funny.
17.And finally, while filming Good Will Hunting, Robin Williams improvised an entire speech about his character's late wife that nearly made Matt Damon break character, starting with, "She used to fart in her sleep. One night it was so loud it woke the dog up."
