Apple TV has greenlit the horror thriller series “Ascension” from Alfonso Cuarón with Caitríona Balfe attached to play the lead role, Variety has learned.

Cuarón has been working on the series for years, with word of it first breaking in 2017 with Casey Affleck originally attached to star. It is inspired by the novel “Last Days” by Adam Nevill.

The logline for the show states that it follows Rose (Balfe), “a relentless documentary filmmaker and recently divorced mother, brilliant at uncovering others’ truths but struggling to resolve her own. When Rose begins a project on a mysterious 20th-century cult known as the Church of Ascension, she finds unexpected refuge in its teachings – until she discovers something far more insidious beneath.”

Alfonso Cuarón is co-writer on the series along with his brother Carlos Cuarón as well as Natalie Erika James (“Apartment 7A,” “Relic”) and Christian White (“Apartment 7A,” “Relic”), with all four executive producing. James and White also serve as co-showrunners, with James serving as lead director. Balfe will executive produce in addition to starring. Alfonso executive produces under his Esperanto Filmoj banner, which has an overall TV deal with Apple.

Esperanto Filmoj’s Gabriela Rodriguez and Richard Schwartz will executive produce. Steve Golin, David Levine and Zack Hayden executive produce for Anonymous Content. Anonymous will produce the show, with Apple Studios serving as the studio.

This marks Alfonso’s second Apple TV series. He previously created the limited series “Disclaimer,” which starred Cate Blanchett, Kevin Kline, Sacha Baron Cohen, and Lesley Manville among others. The show aired in late 2024. Alfonso is primarily known for his films, having received 11 Oscar nominations in his career. He and Carlos shared the nomination for best original screenplay for the acclaimed film “Y tu mamá también,” which Alfonso directed. He then won two Oscars — best director and best editing — for “Gravity” in 2014, followed by four nominations for two wins — best director and best cinematography — for “Roma” in 2019. His other film credits include “Children of Men” and “Harry Potter and the Prisoner of Azkaban.”

He is repped by WME, Blue Marble Pictures and Ziffren Brittenham.

Balfe is also returning to Apple for her second project, with the actress among the cast of the upcoming Apple original film “Tenzing.” She is best known for her starring role in the hit Starz drama “Outlander,” which wrapped up after eight seasons earlier this year. Balfe received four Golden Globe nominations for her work on that show. Her film credits include “Belfast” (which earned her another Golden Globe nod), “Ford v. Ferrari,” “Now You See Me,” and “Super 8.”

She is repped by WME, Emptage Hallett, Cognition, and Jackoway Austen Tyerman. James is repped by WME, 3 Arts, and Sloane Offer. White is repped by TFC Management, RGM Artists in Australia and Gochman Law Group