Natascha McElhone and Bokeem Woodbine are among six actors joining the adaptation of the hugely popular video game franchise.

Showtime's big-budget adaptation of Halo is filling out its cast.

Six actors — Natascha McElhone, Bokeem Woodbine, Shabana Azmi, Bentley Kalu, Natasha Culzac and Kate Kennedy — have signed on to the drama based on the mega-popular video game franchise, which will dramatize the conflict between humanity and an alien race known as the Covenant in the 26th century.

They join Orange Is the New Black's Pablo Schreiber, who is playing the iconic Master Chief role, and newcomer Yerin Ha, who will play a new character in the Halo universe: Quan Ah, a shrewd 16-year-old who meets Master Chief at a fateful time for them both.

McElhone (Designated Survivor, Californication) will play two roles: Dr. Catherine Halsey, the brilliant, conflicted curator of the Supersoldiers, and Cortana, the most advanced AI in human history who may be the key to the survival of the human race.

Emmy nominee Woodbine (Fargo, Spider-Man: Homecoming) plays Soren-066, a morally complex privateer at the fringes of civilization. His fate will bring him into conflict with his former military masters and his old friend, the Master Chief. Acclaimed Indian actress Azmi will play Admiral Margaret Parangosky, the head of the Office of Naval Intelligence.

Kalu, Culzac and Kennedy are all playing characters new to the Halo universe. Kalu's Spartan Vannak-134 is a cybernetically enhanced soldier and de factor deputy to Master Chief. Culzac's Spartan Riz-028 is a focused, professional and cybernetically augmented killing machine. Kennedy's Spartan Kai-125 is courageous and curious — and also deadly.

Halo, which Showtime has described as its "most ambitious series ever," is set to begin production in Budapest in the fall. The nine-episode series has two showrunners in Kyle Killen (Awake, Lone Star), who is overseeing the writers room and stateside production, and Steven Kane (The Last Ship), who will be in charge of physical production in Hungary. Killen was initially announced as the sole showrunner, but as reported in March by The Hollywood Reporter, he wanted a partner who could be on the ground full-time in Hungary.

Otto Bathurst (Black Mirror: The National Anthem) is directing, having stepped in for original helmer Rupert Wyatt, who left the show due to a scheduling conflict.

Halo is one of the most popular video game franchises in the world, having sold more than 77 million copies since its initial release in 2001. The series comes from Showtime, Amblin Television and Microsoft/343 Industries; Killen, Kane, Bathurst, Amblin's Darryl Frank and Justin Falvey, Toby Leslie, Scott Pennington and Karen Richards executive produce.