'I am Iron Man' - probably the most iconic line from the film if not the entire Marvel franchise, would you agree? Well, it was ad-libbed by Robert Downey Jr. believe it or not.
Kevin Feige, President of Marvel Studios, said that the short and snappy line was said by Downey Jr. when the first film was released, a decade ago.
We wonder whether there were some strange looks knocking around the studio.
In an interview with Deadline, Feige said the impact the line had on The Marvel Universe at large was also far-reaching.
"That success inspired us to go further in the trusting ourselves to find balance of staying true to the comics and the spirit of the comics but not being afraid to adapt and evolve and to change things."
NME reported that he also said that part of the success of the line came from how it developed the character of Tony Stark further.
"If you're changing something for no reason, that's one thing, but if you're changing something because you want to double-down on the spirit of who the character is? That's a change we'll make.
"Tony Stark not reading off the card and not sticking with the fixed story? Him just blurting out 'I am Iron Man?' That seems very much in keeping with who that character is."
According to Joe Russo, director of Avengers: Infinity War, Iron Man was pivotal to the subsequent success of the franchise saying: "When you talk about Marvel's rise, Iron Man set the tone of all of it."
Joe Russo knows.
And so does everyone else by the looks of things because Robert Downey Jr. has previously been hailed as Marvel's Best Movie Actor. Ever.
According to Ranker, Downey Jr pips James McAvoy, Tommy Lee Jones and Hugh Jackman to the number one spot. Elsewhere on the list, Ryan Reynolds was at number 53 with Deadpool, harsh.
But, I think we can all agree that Robert is a deserving winner, can't we?
The 53-year-old actor is a big martial arts fan and has been practising 'Wing Chun' since 2003. He has incorporated his training into some of his movies, with his teacher Eric Oram saying: "Robert does all his own stuff when it comes to fights. When the camera is on him, it's really him doing it." What a show off.
He's gone on to have three Iron Man sequels, as well as starring in The Avengers, The Avengers: Age of Ultron, Captain America: Civil War and most recently, Avengers: Infinity War.
We guess the ad-libbing paid off after all then?
Featured Image Credit: PA/Paramount Pictures