Ridley Scott's "Alien: Covenant," the sort-of sequel to "Prometheus," continues to add to its cast. Deadline Hollywood is reporting that Billy Crudup is in talks to join in a secret mystery role. First, Crudup will be joining director Pablo Larrain's "Jackie." The biopic of Jackie Onassis Kennedy will star Academy Award winner Natalie Portman in the titular role. After that, Crudup may be off to fight xenomorphs.

Should he officially sign on, he would join a cast that includes Michael Fassbender (reprising his "Prometheus" role as David the android), Katherine Waterston ("Inherent Vice"), Danny McBride ("Eastbound and Down"), Demian Bichir ("The Hateful Eight"), Jussie Smolett ("Empire"), Amy Seimetz ("Upstream Color"), Carmen Ejogo ("Selma") and Callie Hernandez ("Machete Kills").

"Alien: Covenant" is designed as a follow up to "Prometheus," though it will not include Noomi Rapace's main character Elizabeth Shaw. It will serve as the second chapter in a prequel trilogy to Scott's 1979 iconic "Alien." The story will revolve around the colony ship Covenant, headed to a remote planet on the outskirts of the galaxy. There, the crew discover what they believe to be an uncharted paradise, but is actually filled with danger and horror. The only inhabitant is David, the sole survivor of the Prometheus expedition.

Jack Paglen ("Transcendence") and Michael Green ("Green Lantern") are penning the screenplay. 20th Century Fox will be distributing the film.

Crudup was last seen in 2015's "Spotlight" and Kyle Patrick Alvarez's "The Stanford Prison Experiment."

"Alien: Covenant" is scheduled for an Oct. 6, 2017 release.