Apple TV has formally ordered "Ascension," Alfonso Cuarón's long-gestating horror thriller series, with "Outlander" star Caitríona Balfe now confirmed in the lead role. The project has been in development since 2017, when Casey Affleck was originally attached, and its official greenlight marks a significant step forward for Cuarón's second Apple TV venture after 2024's "Disclaimer." The casting of Balfe, fresh off her eight-season run on "Outlander," gives the show a recognisable lead as it moves towards production.

Adapted from Adam Nevill's novel "Last Days," the series follows Rose (Balfe), a documentary filmmaker investigating a mysterious 20th-century group called the Church of Ascension, who finds herself drawn into its teachings before uncovering something sinister beneath them. Cuarón co-writes and executive produces alongside his brother Carlos, with Natalie Erika James and Christian White also writing and serving as co-showrunners, James directing. The show is produced by Anonymous Content and Apple Studios, with Balfe also executive producing; separately, she is set to appear in Apple's forthcoming film "Tenzing," while Cuarón brings his eleven Oscar nominations and two wins, for "Gravity" and "Roma," to the project.