One of the founding members of the comic book Avengers will appear in the Ant Man movie, as we will see Wasp making a cameo.
In the comics Janet Van Dyne was Hank Pym’s wife, and as suspected there will be a brief flashback to the duo working as secret agents for S.H.I.E.L.D. and in costume as Wasp and Ant Man.
Marvel’s Kevin Feige explained to Collider how we’ll see her:
“Wasp as a superhero in this movie. How much does that factor in it?
FEIGE: It factors in, in a number of spoiler-ish ways, but we will see Janet Van Dyne in action in this film. And part of sort of what happened to her. And then we will understand why that is the reason that he doesnâ€™t want his daughter to follow in those footsteps. One of the reasons why heâ€™s always so upset about superheroes in general, dismissive of them in general and also a reason why he doesnâ€™t want her to put on the suit.”
“Can you tell us whoâ€™s playing the younger version of Hank and Janet?
FEIGE: Michael Douglas is playing the younger version of Hank, and we only see Janet when sheâ€™s in the helmet. Sheâ€™s in the outfit. So you just sort of see eyes.”
So it sounds like we’ll only see Janet in the Wasp costume in the movie. Most fans expect Hope Van Dyne to take up the Wasp mantle and be the new MCU Wasp (she definitely has the haircut), but it’s not known yet if that will happen in this movie or not.