“American Psycho” director Mary Harron is one step closer to tackling one of the most infamous crimes in history. Matt Smith (“The Crown”) and Suki Waterhouse (“The White Princess”) have been added to the cast of “Charlie Says,” Harron’s upcoming drama about the Charles Manson murders. The Hollywood Reporter broke the news. The pic will be introduced to buyers in Berlin later this month.

Based on Ed Sanders’ “The Family” and Karlene Faith’s “The Long Prison Journey of Leslie Van Houten,” “Charlie Says” follows the three young women — known as members of the “family” — who were sentenced to death for their involvement in the crimes. Their sentence changed to life imprisonment when the death penalty was lifted. Faith was “sent in to teach them, and through her the film will follow their transformations as they face the reality of their horrific crimes,” THR summarizes.

Hannah Murray (“Game of Thrones”), Odessa Young (“High Life), and Marianne Rendon (“Imposters”) will play the convicts, and Merritt Wever (“The Walking Dead”) has signed on to portray Faith.

“American Psycho” co-writer Guinevere Turner penned the script.

“Guinevere Turner’s script brings a fresh and unique perspective to the infamous story of the Manson murders and we have now found the perfect cast to bring it to life,” said Harron.

“Charlie Says” is slated to shoot in LA in the spring.

Harron directed every episode of Margaret Atwood adaptation “Alias Grace.” Inspired by true events, the critically acclaimed miniseries tells the story of an Irish immigrant charged with murdering her employers in Upper Canada. The project debuted on Netflix in November.