The Hollywood icon was a surprise addition to the cast of the Marvel Cinematic Universe movie, which stars Paul Rudd and Evangeline Lilly in the titular roles as well as Michael Douglas as Hank Pym -- the original Ant-Man.
Reed recently opened up about Pfeiffer's role as Janet Van Dyne, the original Wasp, and explained that he had woven the character's flashback appearance in 2015's Ant-Man in the hopes of persuading the 60-year-old actress to join the cast.
"We used a double on the first movie," he explained to The Hollywood Reporter. "But the whole thing was, 'I want her to look like Michelle Pfeiffer because that would be my dream casting for Wasp.' We cast this woman to be in the mask who had really saucer-like, Michelle Pfeiffer eyes."
The "Batman Returns" actress disappeared from the limelight for more than a decade, before reappearing in Darren Aronofsky's 2017 feature "Mother!" and Reed admitted it wasn't easy to get Pfeiffer on board with the superhero project.
"I had no idea if she would even be remotely interested in doing this kind of a movie again or how she'd feel about it," the 54-year-old continued. "She came over and sat in one of the conference rooms, just the two of us at Marvel, and kind of talked through who Janet Van Dyne was in the comics and who she might be in this movie."
After giving the actress some of the comics and explaining that the production would beef up Janet's two-dimensional portrayal, Pfeiffer signed on for the role.
"We talked about what it could be, and I wanted her input throughout in terms of the character, without giving too much away," Reed added. "But for me, it was a thrill to be working with her, because she is incredible."
"Ant-Man and the Wasp" is now in theaters.