Star Wars Episode V: The Empire Strikes Back (1980)
Director – Irvin Kershner
As smuggler-turned-hero Han Solo (Harrison Ford) is about to be encased in carbonite, Princess Leia (Carrie Fisher) reveals her love for him. The script called for Leia to say “I love you” to which Solo was supposed to respond with “I love you too”.
Ford decided that Solo wouldn’t say something like that and instead, changed the line to simply “I know.”