Warner Bros. has published the first image of Brolin in the character on the Internet.
The film is an adaptation of the comic of the same name, created by John Albano and Tony DeZuniga.
Jonah Hex is a disfigured cowboy. His adventures take place in the Wild West in the 1970s. Hex is a bounty hunter attempting to stop a voodoo doctor from raising an army of the living dead.
The screenplay was written by Mark Neveldine and Brian Taylor, who also brought us Pathology. Jimmy Hayward (Horton Hears a Who!) will direct.
Jonah Hex, which also stars Megan Fox, John Malkovich, Will Arnett and Michael Shannon, will open in theatres on June 18, 2010.
Josh Brolin is currently shooting Wall Street 2: Money Never Sleeps in New York. The sequel, scheduled to hit theatres on April 23, also stars Michael Douglas and Shia LaBeouf.