The film revolves around a boy named Billy Batson who can transform into an adult superhero by uttering the magic word "Shazam!".
Fulton will play one of Batson's friends, reported Variety.
Filmmaker David F Sandberg is directing from a screenplay by Henry Gayden and Darren Lemke.
DC and Warner Bros are also currently developing a standalone film about Black Adam, Shazam's arch nemesis. Dwayne Johnson is attached to play the titular role.