The actor, who plays Everett Ross in films, says that even though he was "in and out of it quite quickly," the experience filming the recent sequel was "strange and sad."
Martin explained that, despite there being "scores and scores of people on set" who were united to make the film, there was still obviously someone missing.
"There's also no question that, at the heart of it, there's quite a gap now, and you felt it," Martin shared in an interview with Collider.
He later added, "Of course, it was odd with Chadwick not being there. There's no way around that. I think everyone would find it pretty strange and sad."
Martin noted that he didn't even think that another movie would be made after Chadwick's passing, but he realized "there are still other stories to tell within that world and other great characters."
He also commended director Ryan Coogler for making the best of the situation and allowing the actors to still have fun on set.
"With full respect to Ryan Coogler and everybody else, who's sweating and bleeding to get this thing done properly, it was fun. It was enjoyable," Martin said.
And overall, Martin believes they made a film that people will love, despite Chadwick's overwhelming absence.
"I think, and I hope that we've made a good film. I trust Ryan Coogler a lot," Martin concluded.