'Maniac': How Justin Theroux's Freewheeling Performance Came Together

Maniac - Justin Theroux - Publicity-H 2018
Michele K. Short / Netflix

[This story contains spoilers from Netflix's Maniac.]

There's a lot about Netflix's mind-bending new limited series Maniac that viewers won't see coming, from its genre-hopping fantasy sequences to its surreal dystopian vision of New York. But Justin Theroux's gleefully unhinged wildcard performance as Dr. James Mantleray, the mastermind behind a clinical trial that aims to cure mental illness through psychotropic drugs, takes the cake.

Between his physical tics, his questionable toupee and his deeply unhealthy, quasi-Oedipal relationship with his overbearing yet dismissive mother Greta (Sally Field), Mantleray is a bewildering and thoroughly entertaining spin on the mad scientist trope.

"I never quite knew what Justin was going to do in any given moment," showrunner Patrick Somerville, who previously worked with Theroux on The Leftovers, tells The Hollywood Reporter. "With his hair flips, his intonation, moments like when he misses his pocket with his pen — all of that stuff, both he and Sally were always throwing in new jokes, new takes, sidebarring, doing unexpected things. The two of them were amazingly improvisational, and that comic energy coming into the show is great."

Theroux was quick to downplay the idea that he had improvised much of Mantleray when THR caught up with the actor at Maniac's New York premiere.

"I think Patrick's taking credit away from himself, because most of it was on the page," Theroux says while confirming that the character came together through a lot of spontaneous experimentation. "[Mantleray] was the one opportunity in the show to have a little bit of fun comedically, and I really took advantage of that. A lot of it was last-minute decisions: When he's about to see his mom, I was like, 'Wouldn't it be funny if he's putting on lip balm here, because he's so self-conscious about seeing his mother?' And even when we kissed, and it sort of goes on a little too long, that was another moment where we decided to just try it."

On that particular excruciating moment, Theroux added, "Who doesn't want to kiss Sally Field?! She really is heaven to work with, she's hilarious, she's fun, she's game and she's a pro."

Maniac is now streaming on Netflix.