The actress has been a favorite to play the grown-up Beverly Marsh in the director's follow-up to his record-breaking Stephen King horror hit since before the film hit cinemas in September, and now it seems she's on board.
The actress, who worked with Muschietti on his directorial debut "Mama," has revealed she hopes to get a call from the moviemaker before he starts work on the "It" sequel.
"Well, I love Andy and Barbara (Muschietti), I worked with them on Andy's directorial debut ... his first film," Chastain tells ScreenRant. "Barbara is one of my best friends, so ... we'll see.
"Listen, of course, I want to work on it ... they're my friends. They're like my family. Anything that they're doing I want to be a part of, so I hope we can make it happen."
The hit adaptation of King's 1986 novel revolves around a group of small-town youths battling a monster named Pennywise in the 1950s.
The sequel moves on 30 years into the future and revisits the kids as adults, who must return to their native Maine to tackle their worst nightmares once again.
It appears Chastain's casting is almost a certainty, barring scheduling conflicts -- because Muschietti has publicly stated he wants her in the sequel: "She is an amazing actress and a very good friend and I would love her to play Beverly," he recently said. "She loves the movie and it feels like the planets are aligned in that sense."