The most iconic scene in “Avengers: Endgame” was also the final scene shot for the Marvel Studios blockbuster, featuring Robert Downey Jr.’s Tony Stark and an epic snap of his fingers.

On Friday, the actor’s personal assistant, Jimmy Rich, shared a brief clip of Downey filming the scene against a green-screen background in a reshoot that came together after principal photography on the film had completed.

In an interview with /Film, “Endgame” directors Joe and Anthony Russo explained how that particular scene — which was not in the original script and was filmed just three months before the film’s premiere — came to be.

RELATED: Jon Favreau Says Robert Downey Jr. Deserves A Oscar Nod For ‘Avengers: Endgame’: ‘He Has My Vote’

“Tony used to not say anything in that moment,” one of the Russos told the site. “And we were in the editing room going, ‘He has to say something. This a character who has lived and died by quips.’ And we just couldn’t, we tried a million different last lines. Thanos was saying ‘I am inevitable.’ And our editor Jeff Ford, who’s been with us all four movies and is an amazing storyteller, said, ‘Why don’t we just go full circle with it and say I am Iron Man.’ And we’re like, ‘Get the cameras! We have to shoot this tomorrow.’”

Click to View Gallery
Most Memorable Moments From The ‘Avengers: Endgame’ Press Tour