'X-Men' Spinoff Series 'Legion' Casts Dan Stevens, Aubrey Plaza, And Jean Smart

Ever since leaving Downton Abbey Dan Stevens has built himself into a solid leading man on the big screen, starring in the cool genre thriller The Guest, and securing roles in Colossal opposite Anne Hathaway, followed by Beauty and the Beast alongside Emma Watson. But a return to TV is in the cards for him now, as part of FX's upcoming X-Men spinoff series, Legion.

Stevens will take the lead role of David Haller, a diagnosed schizophrenic who also happens to be the son of X-men leader, Charles Xavier. He's been confined to a mental institution most of his life, but just as he's beginning to lose hope an encounter with a fellow patient leads him to believe he crazy visions he's seeing are actually real. Also joining the cast are Aubrey Plaza as Lenny, David's friend who retains her optimism despite being an alcohol and drug abuser. Jean Smart, an alum of FX's Fargo just like the previously-cast Rachel Keller, plays Melanie, a nurturing and unconventional therapist.

Production on the Legion pilot begins next month.