Newcomer Jeremie Harris has reportedly joined the cast of FX's upcoming X-Men spinoff, Legion. THR broke the story that he'll be joining the cast as a new character called Ptonomy, described as an "outsider by nature, stand-offish and sardonic, who is a former child prodigy who feels trapped in the past." There's no firm confirmation that he's a mutant, but how many parents have looked down at their new-born, normal human child and said "yes, he's definitely a Ptonomy"? Harris will be joining a cast headed up by Dan Stevens, who takes the lead role of David Haller, a mutant with split personality disorder - and a different mutant power for each personality. Fans of Marvel Comics will recognise Haller as being the son of one Professor Charles Xavier, but it remains to be seen if this connection will be retained in the show. Probably not, considering showrunner Noah Hawley's (Fargo) claims that "it's conceived more as a standalone" show, and the likelihood of getting James McAvoy or Patrick Stewart to make an appearance is slim anyway. Also starring are Aubrey Plaza and Fargo's Jean Smart & Rachel Keller, the latter being the love interest of the show. Dan Stevens' star is on the rise, with solid performances in The Guest and A Walk Among the Tombstones. He's also got a starring role as the titular beast in Bill Condon's big-screen Beauty and the Beast, opposite Emma Watson. It remains to be seen whether the lead role in Legion will be a step forward or backward for the actor. Production on Legion begins in March.