The annual comic book convention and entertainment event is taking place over this weekend in San Diego, California from 21 July to 24 July.
To the delight of fans, Johnson turned up in full costume to promote his forthcoming film Black Adam.
He arrived at the event in a cloud of smoke and crackling electricity, which cleared to reveal Johnson in full costume as the superhero.
The crowd was treated to an extended look at the forthcoming film, which stars The Rock as the titular Marvel anti-hero who is bestowed with the powers of the Egyptian Gods.
During the Q&A that followed, Johnson made a playful jibe at Kevin Hart.
He was asked by a young fan in the crowd: “Mr Rock, when you got the job as Black Adam, did Kevin Hart ever get jealous?”
“Mason, that was a great question,” Johnson replied. “The truth is yes, Kevin Hart gets jealous of everything.”
“And you know, I’m pretty good with height and you’re already taller than Kevin Hart.”
The two actors are friends, having starred together in numerous films, including Jumanji and the recently released animated movie DC League of Super-Pets.
Elsewhere during Marvel’s huge panel at Comic-Con, the “stunning” first trailer for Black Panther 2 was unveiled.
Black Adam is slated for release on 21 October.