Mackie plays Sam Wilson, aka Falcon, in the Marvel Cinematic Universe, and in the final installment of the Avengers franchise, Evans' Steve Rogers retires as Captain America as he hands over his famous shield to his flying sidekick.
Evans was so excited to find out the unexpected ending of his tenure as the superhero that he rushed to share the news with Mackie before he'd had chance to read the script for himself.
Mackie told IMDb, "We were at his house and he goes, 'You excited?' And I go, 'What are you talking about?' and he goes, 'You don't know?' He jumps up, runs out of the room and comes back in with the script."
After reading the ending with Evans, the "8 Mile" star admitted he was "blown away".
"We cried. We drank. We laughed," he shared. "I am very happy I got that moment with Chris, for him to not only pass me the shield, but to tell me it was happening."
The actors first worked together as Captain America and Falcon in 2014's "Captain America: The Winter Soldier", which was also directed by Endgame filmmakers Anthony and Joe Russo.
And filming the closing scenes on Endgame was incredibly emotional for Mackie, as the father-of-three admitted the significance of becoming the first black Captain America began to really dawn on him.
"It means a lot to me for my sons to see Captain America as a black dude and for me to be that dude to my sons," the 40-year-old continued. "So that moment was not just, 'Hey, we're acting.' It was more of a thing. And then they (the Russo brothers) cut and I cried. And Chris cried. And the Russos cried. And everyone cried. It was an emotional day."