Jason Isbell and Sturgill Simpson have joined the cast of Martin Scorsese’s new movie Killers of the Flower Moon. The film is based on David Grann’s nonfiction account of the serial murder of members of the oil-wealthy Osage Nation in 1920s Oklahoma which became known as The Reign of Terror.

The two Grammy-winners join an already stacked cast full of Scorsese regulars. Leonardo DiCaprio stars as Ernest Burkhart, the nephew of a powerful local rancher played by Robert De Niro, while Jesse Plemons plays the FBI agent investigating the murders. Isbell, in his first acting role, will play Bill Smith who is an adversary of Dicaprio’s character, while Simpson will play a rodeo star and infamous bootlegger Henry Grammer. Killers of the Flower Moon‘s cast also includes Lily Gladstone, Tantoo Cardinal, Cara Jade Myers, William Belleau, Louis Cancelmi, JaNae Collins and Jillian Dion.

While this is Isbell’s first speaking role, he did have a cameo in the 2019 Deadwood movie. On Twitter her simply remarked ,”When I say I am EXCITED.” Simpson, meanwhile, has had roles in Queen and Slim and Jim Jarmusch’s The Dead Don’t Die.

The film, which features a screenplay by Eric Roth (Munich, The Insider, Forrest Gump), is being made for Apple Films.