FX has reportedly cast Downton Abbey star Dan Stevens to play David Haller, the title star of the upcoming X-Men television series Legion, according to Deadline. Stevens will reportedly be joined by two actresses; Aubrey Plaza playing a friend of David's named Lenny, while Jean Smart plays Haller's therapist.
Deadline describes Legion's plot as follows:
Legion introduces the story of David Haller (Stevens), based on the Marvel comics character Legion, the son of X-Men founder Charles Xavier. Since he was a teenager, David has struggled with mental illness. Diagnosed as schizophrenic, he has been in and out of psychiatric hospitals for years. A haunted man, David is getting tired of finding his way back to sanity and is about to give up when he meets the girl of his dreams, a fellow patient. After the strange encounter, he’s confronted with the possibility that the voices he hears and the visions he sees might be real.
Aubrey Plaza's Lenny character is drug and alcohol addict with a surprisingly optimistic view that "any day now her life is gonna turn around."
Jean Smart's therapist Melaine is described as both "nurturing" and "demanding, with "a sharp mind and unconventional methods."
Deadline said the previously cast Rachel Keller will play a "self-sufficient and street-smart" woman named Syd with a hard exterior but a "soft core."
No timeline has been given for Legion to debut, although a pilot has been ordered by FX.