FX's 'Legion' Cast Will Lead You Down The Rabbit Hole Of The New Superhero Series
Chris Large/FX

It seems clear from the trippy advertisements and glowing reviews that the new FX drama Legion, whose cast is led by Downton Abbey's Dan Stevens, is going to be unlike pretty much any superhero show currently on television. That's an impressive feat, considering how long that list is; practically every network on television can stake a claim in the comic book genre, including ABC (Agents Of S.H.I.E.L.D.), FOX (Gotham), NBC (Powerless), AMC (Preacher), The CW (with its Arrowverse), and Netflix (with its various Marvel Defenders series).

But Legion looks to have more in common with the mind-bending likes of Westworld and Mr. Robot than that list of superhero programs thanks to its protagonist, a man suffering from dissociative personality disorder. The question of what is real and what is imaginary is bound to loom large throughout the new show by Fargo creator Noah Hawley. It's essential, then, that Legion have terrific actors who are capable of grounding the hallucinatory plot in believable motivations and stakes, or it could all get too difficult for the audience to digest.

Thankfully, Hawley looks to have that aspect of his show already in the bag. Here are the talented men and women who will be leading us on this fantastical journey, starting with Legion himself:

1. Dan Stevens as David Haller

Frank Ockenfels/FX

This will be Stevens' first regular role on a TV series since his three-season stint as Matthew Crowley on Downton Abbey ended in tragedy. In the five years between those two projects, Stevens has mostly been focusing on his film career, with roles in the likes of the Julian Assange biopic The Fifth Estate, the horror movie The Guest, the Liam Neeson action movie A Walk Among The Tombstones, the upcoming Anne Hathaway monster movie Colossal, and of course the live-action remake of Beauty And The Beast, hitting theaters next month.

2. Jean Smart as Melanie Bird

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Smart is making the transition to Legion with her former Fargo showrunner, for whom she played steely matriarch Floyd Gerhardt on Season 2 of that crime drama. That role earned the prolific actress her eighth Emmy nomination (including three wins); her other awards-worthy performances have included roles in Harry's Law, Samantha Who?, 24, The District, and Frasier. On the big screen, you may have seen Smart in the likes of Sweet Home Alabama, Garden State, I Heart Huckabees, and The Accountant.

3. Aubrey Plaza as Lenny Busker

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Like Stevens, Legion marks Plaza's first regular television role since the show that made her famous: in Plaza's case, that's Parks And Recreation, on which she played the hilariously deadpan April Ludgate for seven seasons. Her feature film credits include Scott Pilgrim vs. the World, Safety Not Guaranteed, Life After Beth, Dirty Grandpa, Mike And Dave Need Wedding Dates, and two films that premiered at Sundance last month: the period parody The Little Hours and the award-winning thriller Ingrid Goes West.

4. Rachel Keller as Syd Barrett

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Keller's resumé may be less lengthy than those of her more famous co-stars, but many Legion fans will likely recognize the young actress if they also watched Hawley's previous FX endeavor. Keller also appeared in Season 2 of Fargo, playing Floyd's rebellious and strong-willed daughter Simone Gerhardt. (Her only other TV credits are one-episode guest spots on The Mentalist and Supernatural.)

5. Bill Irwin as Cary Loudermilk

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Irwin's film credits are as varied as How The Grinch Stole Christmas, Lady In The Water, Rachel Getting Married, and Interstellar. He was a regular guest on Sesame Street through the '90s and '00s, and his other TV appearances include recurring roles on the likes of CSI, Sleepy Hollow, and Law & Order: SVU. In 2005, he won a Tony Award for his performance in the Broadway revival of Who's Afraid Of Virginia Woolf? in which he starred as George opposite Kathleen Turner as Martha.

6. Amber Midthunder as Kerry Loudermilk

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Midthunder comes to Legion after appearing in other cult-favorite genre TV shows like Banshee, Longmire, and The Originals. She can also currently be seen in the Best Picture nominee Hell Or High Water.

7. Jeremie Harris as Ptonomy Wallace

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Harris has worked with his Legion co-star Stevens once before, also appearing in the 2014 action movie A Walk Among The Tombstones. His resumé also includes guest spots on Person Of Interest and Blue Bloods, as well as a role in the acclaimed 2011 indie drama Pariah.

8. Katie Aselton as Amy Haller

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Aselton joins the new FX show two years after The League — in which she starred as Jenny alongside Mark Duplass and Nick Kroll — ended its seven-season run on the same network. You may also have caught her guest starring on some of your favorite shows like The Office, Burning Love, Revolution, Togetherness, and Casual.

9. Jemaine Clement as Oliver Bird

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Clement may undoubtedly be best known as one half of the musical comedy duo known as Flight Of The Conchords (which also had its own show for two seasons on HBO that ran from 2007-'09), but he's also a prolific voice actor, lending his vocal talents to movies like Despicable Me, Rio, Men In Black 3, The BFG, Moana, and the upcoming spinoff The Lego Batman Movie.

Let this terrific cast lead you down the rabbit hole when Legion premieres on FX this Wednesday at 10:00 p.m. ET.