Netflix's forthcoming Sabrina-themed Riverdale spinoff is starting to take shape.

Actress Jaz Sinclair (Easy, The Vampire Diaries) has been tapped to co-star opposite leading lady Kiernan Shipka.

Picked up with a two-season, straight-to-series order, the untitled Sabrina show reimagines the origin and adventures of the comic book character Sabrina the Teenage Witch as a dark coming-of-age tale that traffics in horror, the occult and witchcraft. It's described as in the vein of Rosemary's Baby and The Exorcist and finds Sabrina wrestling to reconcile her dual nature as a half-witch, half-mortal, while fighting the evil forces that threaten her, her family and the daylight world humans inhabit. The untitled drama's Sabrina Spellman is described as an empowered young woman — half-human, half-witch — who is just beginning her dark education as a sorceress, even as she tries to maintain a normal life as a sophomore at Baxter High. Intelligent, compassionate and brave to the point of recklessness, Sabrina is all that stands between us and the forces of darkness that threaten our world.

Sinclair will take on the series regular role of Rosalind Walker, the brash, empowered and outspoken daughter of Greendale's minister and Sabrina's (Shipka) best friend at Baxter High.

Sinclair's credits include Netflix's Easy and the upcoming Screen Gems horror feature Slender Man. She's repped by UTA, Creative Partners Group and Hirsch Wallerstein.

Riverdale showrunner Roberto Aguirre-Sacasa, who also serves as chief creative officer of Archie Comics, penned the script for the untitled series. Aguirre-Sacasa will direct the drama and executive produce alongside Riverdale collaborators Greg Berlanti, Sarah Schechter, Archie Comics CEO Jon Goldwater and Lee Toland Krieger. The drama hails from Warner Bros. Television-based Berlanti Productions.