The film, which may be split into two parts, will begin filming this summer.
"Beasts of No Nation" director Cary Fukunaga was originally attached to direct, but reportedly backed out of the project over creative differences, reported Variety.
Andres Muscietti, who directed the 2013 horror short "Mama", is now helming the movie.
"It" follows the lives of a group of friends known as the Losers' Club, who together face the evil "It" monster after it takes on the form of Pennywise the Dancing Clown.