Chastain was always a pretty solid guess when it came to adult Beverly. After all, she worked with It director Andy Muschietti on the 2013 horror film Mama. There's also the fact that Muschietti said he already had Chastain in mind for the sequel back in September 2017, and Chastain even expressed interest in taking on the role. In February, she was as good as locked in. Talk about a perfect storm of circumstances!