Leonardo DiCaprio and Martin Scorsese are officially reteaming.

Imperative Entertainment has attached Scorsese to direct and DiCaprio to star in the feature adaptation of “Killers of the Flower Moon,” the New York Times best-selling book by David Grann.

Imperative acquired the rights to the book in 2016. DiCaprio and Scorsese quickly expressed interest in the project, and have been loosely attached since 2016.

Scorsese will produce alongside Imperative Entertainment’s Dan Friedkin, Bradley Thomas, Sikelia Productions’ Emma Tillinger Koskoff, and Appian Way Productions. Eric Roth is penning the script. The pic is expected to be both Scorsese and DiCaprio’s next project.

“When I read David Grann’s book, I immediately started seeing it — the people, the settings, the action — and I knew that I had to make it into a movie,” said Scorsese. “I’m so excited to be working with Eric Roth and reuniting with Leo DiCaprio to bring this truly unsettling American story to the screen.”

The story is set in 1920s Oklahoma and revolves around the Osage Nation, who were the richest people per capita in the world, after oil was discovered under their land and then they were murdered, one by one. As the death toll rose, the newly created FBI took up the case and unraveled a chilling conspiracy and one of the most monstrous crimes in American history.

Imperative Entertainment executives have met with the Osage Nation and the team is scouting locations in the coming months with production set to commence during the summer of 2019.

30WEST will arrange the financing and distribution for the project.

The project will mark the sixth film DiCaprio and Scorsese have worked on together, most recently teaming on the Oscar-nominated “The Wolf of Wall Street.” DiCaprio is currently filming Quentin Tarantino’s “Once Upon a Time in Hollywood” and Scorsese is in post-production on his Netflix mob drama “The Irishman.”

Scorsese and DiCaprio are both represented by LBI Entertainment and attorney Steve Warren of Hansen, Jacobson, Teller, Hoberman, Newman, Warren, Richman, Rush & Kaller. Scorsese is also represented by WME.