Gustaf Skarsgard and Fares Fares will be series regulars, while Betty Gabriel will recur as the HBO drama bulks up for its sophomore run.

HBO's Westworld is bulking up for season two.

The Emmy-nominated drama about a whacked-out futuristic theme park has enlisted Vikings star Gustaf Skarsgard and Fares Fares (Tyrant) as series regulars for season two. They are joined by Betty Gabriel (Good Girls Revolt), who will recur.

Skarsgard — who will continue to appear as Floki on History's Vikings — will play Karl Strand, a white-collar guy comfortable in the field. Fares will take on the role of Antoine Costa, a tech expert with an objective perspective. Gabriel will recur as Maling, who is trying to restore order on the ground. All three new characters find themselves in an unpredictable environment during the second season of Westworld.

Season one ended when Dolores (Evan Rachel Wood) made the conscious choice to become Wyatt, a killer personality with an eye toward robot revolution. She fired off the first shot of war directly into the brain of Robert Ford (Anthony Hopkins), signaling that hosts can now kill guests. Elsewhere in the park, Maeve (Thandie Newton) wandered into a section of the Mesa designated "SW," alternately referred in the fandom as "Samurai World" and "Shogun World," the first confirmation that the show, much like Michael Crichton's original movie, contains parks beyond Westworld itself.

The trio join a rapidly expanding cast for Westworld's sophomore run. On board as series regulars are Katja Herbers as Grace, a seasoned guest in Westworld whose latest visit comes at the park's darkest hour; and Neil Jackson as Nicholas, a charming and resourceful man who finds himself in unchartered territory. Jonathan Tucker (Kingdom) will also recur as Maj. Craddock, a commanding military officer.

The series, from showrunners Jonah Nolan and Lisa Joy, has also promoted season one recurring stars Talulah Riley (Angela, the host who welcomed guests to Westworld) and Louis Herthum (who played Dolores' father, Peter Abernathy).

Production on season two of Westworld started in July. It is expected to premiere in 2018.

Skarsgard (The Way Back) is repped by MGMT Entertainment; Fares (Rogue One, Zero Dark Thirty) is with Magnolia Entertainment; and Gabriel (Get Out, The Purge: Election Year) is repped by Greene & Associates Talent and Generate.