Charlie Hunnam (Sons of Anarchy) will star alongside actors Robert Pattinson (The Twilight Saga) and Sienna Miller (American Sniper) in the highly anticipated big screen adaptation of David Grann’s bestselling nonfiction book, The Lost City of Z.

Hunnam is cast in the leading role of legendary explorer Percival Fawcett, a British colonial who went missing in 1925 with his son, when he set out to find a mythical city in Brazil’s Amazon jungle. Gann’s book tells the true story of Fawcett’s quest and relates his own experiences in the treacherous jungle as he tried to unravel the mystery of the famous exploration. Dozens of individuals are believed to have disappeared or perished while searching for Fawcett.

Hunnam is replacing Benedict Cumberbatch, who was slated to play Fawcett, but recently bowed out, reportedly due to his hectic schedule.

Besides his successful television career, Hunnam has established a presence on the big screen in prominent films like Pacific Rim. Among his other upcoming projects are a sequel to Pacific Rim and Guy Ritchie’s feature film adaptation of the Sir Lancelot tale, Knights of the Roundtable: King Arthur.

James Gray is directing and writing the screenplay for The Lost City of Z. He is best known for writing and directing several of Joaquin Phoenix’s pictures, including the crime dramas The Yards and We Own the Night.

The film’s producers include Brad Pitt via his Plan B Entertainment venture.

Production on The Lost City of Z is set to begin this summer, and the film is expected to hit theaters nationwide sometime in 2016.