Avengers Endgame directors Joe and Anthony Russo had shot a number of different last words for Iron Man, however, nothing quite stuck.
It wasn’t until the film’s editor Jeffrey Ford came up with Downey Jr saying, “And I am Iron Man” that the filmmaking brothers realised it had to be that.
After all, this was Downey Jr’s improvised last line at the conclusion of his first Iron Man movie, when Tony Stark revealed to the press the truth of his superhero identity.
The Russos then managed to convince Downey Jr to shoot the line in a soundstage that turned out to be right next door to the one used for his original Iron Man audition.