X-Men spinoff show, Legion, finds its mutants

FX has announced the first cast members for its X-Men spinoff series, Legion, including who will play Professor Charles Xavier's son.

Dan Stevens (Downton Abbey), Aubrey Plaza (Parks and Recreation) and Jean Smart (Fargo) have all signed on for the New Mutants spinoff, Marvel announced today.

Most notable is Stevens' role as David Haller, the schizophrenic son of Charles Xavier and Israeli holocaust survivor, Gabrielle Haller.

As a young teen, Haller was diagnosed with the mental illness and admitted to various psychiatric institutions over the years. It's during one of his stays that he has an eye-opening interaction with another patient that leads him to believe the visions and voices he suffers from may actually be real.

Haller was first introduced to Marvel Comics readers in issue 25 of New Mutants back in 1985. The character later becomes the Israeli ambassador to the U.K.

Plaza, best known for her work as April in Parks & Rec, will play David's close friend, Lenny. Lenny has spent years battling drug and alcohol addictions, but is described as a hopeful and optimistic person who believes her life could change at any second.

Lastly, Smart — who recently played Floyd Gerhardt on FX's Fargo — will pay Melanie. According to the Marvel website, Melanie is a "nurturing, demanding therapist with a sharp mind and unconventional methods."

New Mutants was a spinoff comic book series based on Marvel's popular X-Men that began in 1983 and ran until 1991. When the series ended, the characters that were created and introduced in New Mutants, including Deadpool, were reintroduced as X-Force.

The show is being helmed by Fargo showrunner Noah Hawley, with X-Men: Apocalypse director Bryan Singer on board to executive produce. It's the first show being developed by FX and Marvel with executives from both companies overseeing the series. On top of the series, there's also a New Mutants spinoff film in the works at Fox.

The series is set to start production in March with no premiere date confirmed at this time.