Dan Stevens To Lead FX's X-Men Spinoff 'Legion'

Cousin Matthew is going to be a superhero. Downton Abbey alum and The Guest star Dan Stevens has just been cast to lead FX's X-Men spinoff Legion, alongside Parks and Recreation's Aubrey Plaza and Fargo's Jean Smart. The trio join Fargo breakout Rachel Keller, who was cast last month

Variety reports Stevens will play main character David Haller, who was diagnosed with schizophrenia at a young age. He's spent much of his life going in and out of psychiatric hospitals, trying hard to recover, but he's just about to give up when he meets the girl of his dreams. He begins to wonder if the voices and visions in his head might be real, and not just a symptom of his mental illness. In the X-Men comics, David is the son of X-Men founder Charles Xavier.

Plaza will play David's friend Lenny, who is described as follows: "Despite a life of drugs and alcohol abuse, she knows that any day now her life is gonna turn around, which gives her the likeable energy of the impossible optimist despite her rough demeanor." The "rough demeanor" part sounds right up Plaza's alley, but the "likeable energy of the impossible optimist" part might represent a change of pace for her.

Smart has been cast as Melanie, "a nurturing, demanding therapist with a sharp mind and unconventional methods." As previously reported, Keller is "a scrappy, optimistic young woman in her 20s" who may or may not prove to have superpowers. Legion reunites Smart and Keller with Fargo creator Noah Hawley, who is developing the X-Men spinoff.

Stevens first broke out as Cousin Matthew on Downton Abbey. He departed the series after three seasons, and since then has been working on building up his film career. He turned heads and attracted widespread acclaim as David, the mysterious visitor in The Guest, and has also appeared in The Fifth EstateA Walk Among the Tombstones and Night at the Museum: Secret of the Tomb. Next up for him is Disney's live-action adaptation of Beauty and the Beast, in which he plays the Beast.

Shooting on Legion is expected to get underway in March. The series only has a pilot order from FX at this point, but between its very on-trend concept (superpowers are so hot right now) and its all-star creative team and cast, we're guessing there's a pretty good chance it'll move forward.

Lauren Shuler DonnerBryan SingerSimon KinbergJeph LoebJim Chory, and John Cameron will executive produce the Legion pilot with Hawley, who is also writing. Legion is one of two X-Men-inspired TV projects in development at the moment; the other is Hellfire, a 1960s series set up at Fox.