Aneurin Barnard, who recently broke out in Warner Bros.’ “Dunkirk,” has landed the key role of Boris in the studio’s highly anticipated adaptation of “The Goldfinch.”

Ansel Elgort recently landed the role of Theo. John Crowley is on board to direct.

Warner and RatPac had picked up rights to Donna Tartt’s Pulitzer-winning book back in 2014. RatPac is also an investor on the film as well as a producer. “Goldfinch” tells the story of a young man named Theodore Decker who survives a terrorist bombing at an art museum — an attack that kills his mother. From there, he tumbles through a series of adventures that finds him living in Las Vegas with his deadbeat father and, later, involved in art forgeries.

Earlier this year, Amazon Studios agreed to co-finance the film, which will go into production at the start of 2018. As part of the pact, Amazon will invest more than a third of the movie’s budget, which is estimated to be in the $40 million range, according to insiders. In return, it will get streaming rights to the picture on its Prime service. It will also launch the picture on home entertainment platforms in what is commonly referred to as the pay-TV window, the term for when movies debut on premium cable channels such as HBO and Showtime.

Warner Bros. will distribute the film in theaters worldwide.

Execs had been meeting with actors for the role of Boris for some time, and Barnard had already impressed the studio in his first major tentpole role in “Dunkirk.”

Prior to “Dunkirk,” Barnard’s only other big role was in the limited series adaptation of “War and Peace.” He is repped by WME and the Artists Partnership.