The House of Atreides has gained an ally.

Léa Seydoux has joined “Dune: Part Two” in the critical role of Lady Margot, a vital ally to Paul Atreides (Timothée Chalamet) in his war with the House of Harkonnen.

Director Denis Villeneuve is set to start filming the “Dune” sequel later this year, with Chalamet, Zendaya, Rebecca Ferguson, Josh Brolin, Javier Bardem, Stellan Skarsgard and Dave Bautista set to reprise their roles. They will be joined by new actors Austin Butler (as Feyd-Rautha Harkonnen, heir to the House of Harkonnen), Christopher Walken (as Emperor Shaddam IV) and Florence Pugh (as the Emperor’s daughter, Princess Irulan).

Villeneuve is co-writing the screenplay with Jon Spaihts. Villeneuve, Mary Parent, Cale Boyter and Tanya Lapointe are producing, and Josh Grode, David Valdes, Herbert W. Gains, Brian Herbert, Byron Merritt, Kim Herbert, Thomas Tull, Spaihts, Richard P. Rubinstein and John Harrison are executive producing. Legendary is backing the film.

In Frank Herbert’s novel “Dune,” Lady Margot factors early on into the story, when she leaves a critical warning to Paul’s mother, Lady Jessica (Ferguson), about the treachery that awaits them on Arrakis after House Atreides takes over from House Harkonnen. That sequence didn’t make Villeneuve’s movie, but as a member of the Bene Gesserit, Lady Margot does have a major part to play in the second half of the story, involving Feyd-Rautha and her husband, Count Fenring (a role that has yet to be cast).

Perhaps best known for her performance in the latest James Bond movies, “Spectre” and “No Time to Die,” Seydoux most recently starred alongside Viggo Mortensen and Kristen Stewart in director David Cronenberg’s “Crimes of the Future.”

The first “Dune” earned $400.6 million worldwide, one of the biggest box office grosses of Warner Bros.’ day-and-date releases on HBO Max in 2021; its $41 million domestic debut was the studio’s biggest opening weekend for a hybrid release that year. The film went on to be nominated for 10 Academy Awards, including best picture, and it won six, for sound, visual effects, production design, original score, editing and cinematography.

Deadline first reported the news of Seydoux’s casting.