The 20 most famous movie line of all time was made up on the spot.

‘I’m Walkin’ Here!’

“Midnight Cowboy” a tale of two con men forming an unlikely alliance, is a cinematic masterpiece, with one of its most memorable moments stemming from an unplanned New York City incident. When a taxi nearly hit Dustin Hoffman and Jon Voight mid-scene, Hoffman, maintaining his character as “Ratso” Rizzo, ad-libbed, “I’m walkin’ here! I’m walkin’ here!” This improvisation was so smoothly executed that it was incorporated into the final film.

‘I Know’

The “Star Wars” franchise, with its beloved heroes, villains, and cosmic creatures, has left an indelible mark on cinema. In “The Empire Strikes Back,” Harrison Ford, as Han Solo, improvised a key response that became iconic. After Leia (Carrie Fisher) professes her love, Han, originally scripted to reciprocate her sentiment, instead replies with, “I know.”