Jeremy Irons and Brendan Gleeson have rounded out the cast of New Regency’s adaptation of the popular video game “Assassin’s Creed” starring Michael Fassbender.

Marion Cotillard and Michael K. Williams also star.

Justin Kurzel is directing, with production set to begin in the early fall for a Dec. 21, 2016, release through Fox. The studio decided last September to move the project out of the 2015 summer window.

The Assassin’s Creed video game has sold over 91 million units. The film follows a man who attains the skills of a master assassin after finding out that he is a descendant of a secret society of professional killers.

Irons plays Cotillard’s father. Gleeson plays Fassbender’s father.

“Assassin’s Creed” is co-financed by RatPac and Alpha Pictures. Producers are Frank Marshall, Arnon Milchan, Jean-Julien Baronnet, Conor McCaughan, Fassbender and Pat Crowley. Ubisoft Motion Pictures developed the project and is producing with New Regency.

Gleeson just completed production on “The Free State of Jones” and “Alone in Berlin.” He is repped by The Agency and Principal Entertainment.

Irons can be seen next in “Batman v Superman: Dawn of Justice,” in which he will play Alfred, Bruce Wayne’s butler. He is repped by CAA.

The news was first reported by Deadline Hollywood.