Martin Campbell will direct. Production is expected to begin in January.
Warners and Campbell chose Reynolds, who vied for the superhero role along with “The Hangover” star Bradley Cooper and Jared Leto. The momentum built for Reynolds in the last week, as he was the only actor whose option was extended.
The news caps off a memorable summer for Reynolds, who played Deadpool in “X-Men Origins: Wolverine,” a performance that prompted Fox to begin development on a spinoff film. Reynolds followed that by starring opposite Sandra Bullock in the romantic comedy “The Proposal,” which crossed the $100 million mark this week.
The actor will next star in “Buried,” a dark indie drama that will begin filming shortly in Barcelona with Spanish director Rodrigo Cortes.