When you look at the resume that actor Jessica Chastain has amassed over her entire career, the words "comic book movie," don't come readily to mind. And yet, when Gotham City Sirens announced that Poison Ivy was going to be one of the three titular Sirens in play, her name was one of the first that came to the minds of fans and commentators alike. But while we can wish and hope for a Chastain-cast Ivy in the DCEU, it's only going to happen if she's open to that possibility, and as luck would have it, she totally is. I recently spoke with Jessica Chastain, while she was promoting her latest film The Zookeeper's Wife, and she defined the big factors that would help bring her to the table thusly: