The new giant ant playing a drum kit, but you'll have to look closely to catch a glimpse of the original Wasp. Played by Michelle Pfeiffer, Janet van Dyne was trapped in the Quantum Realm the last time we heard about her, but since she's featured prominently on the poster it's safe to assume that she'll be around for more than just one short scene this time.
In Ant-Man, we saw a flashback in which Janet van Dyne went sub-atomic in order to deactivate a nuclear bomb, and was subsequently lost in the Quantum Realm - a dimension that can only be reached by shrinking down through the spaces between atoms. It's not an easy place to come back from, and Janet has been lost there ever since. However, Scott Lang was able to visit the Quantum Realm and return from it, so it's likely that we'll see Hank Pym and our two heroes execute a rescue mission in Ant-Man and the Wasp.
Related: Ant-Man and the Wasp LEGO Set Teases Quantum Realm Exploration
The the movie's villain, Ghost. However, one shot that definitely shows the original Wasp occurs at around the 1:33 mark, and looks like another flashback scene with Hank and Janet teaming up on a government mission. Hank punches a soldier, and Janet grows to full-size just in time to knock the soldier to the ground. It's a blink-and-you'll-miss-it moment, but you can check out a still below.
Ant-Man and the Wasp looks to offer a Avengers: Infinity War, and the trailers so far have painted it in a similar light to the first movie: a fun adventure with lots of comedy. With that said, any plot involving a family reunion between the long-missing Janet and her husband and daughter is sure to be a bit of an emotional rollercoaster, so expect the story to have some heart as well.
Pfeiffer will also appear in next year's big team-up Avengers 4, which will deal with the fallout from Infinity War and set the stage for whatever's to come in Phase Four of the Marvel Cinematic Universe. It's likely that Janet will end up in a similar role to Hank, providing for Ant-Man and the Wasp from the sidelines, but we won't rule out the possibility of her putting on her old suit and jumping back into the fray just yet.
