Ewan McGregor has his work cut out for him on Fargo.
The actor, who plays two characters in the third season of the acclaimed FX series -- brothers (though not twins) Ray and Emmit Stussy -- opened up to ET at the FX TCA Upfronts earlier this month about the challenges that come with bringing two fully developed people to life.
EXCLUSIVE: Carrie Coon Talks Unexpected ‘Leftovers’ Finale and Joining ‘Fargo’ Season 3
"The biggest challenge for me is that I'm playing two characters, the 46-year-old actor told ET. "Creating two people, two very different people, being believable as both of them, is my biggest challenge."
During the season, the two brothers often have to interact, but that doesn't mean the actor is talking to himself.
McGregor told reporters on a recent conference call that the secret to him playing two characters involves not one, but two stand-ins.
"That's important," McGregor noted, stressing the value of having two separate people to play off of as he switches from Emmit to Ray.
So who does the cast and crew prefer? "Definitely Ray," he said.
And when he's not appearing opposite himself, McGregor often shares scenes with Mary Elizabeth Winstead, who plays Nikki Swango. Ray is Nikki's boyfriend/probation officer, and the two seem primed to get into a whole lotta trouble.
MORE: Ewan McGregor Will Play Brothers in FX's 'Fargo' (and They're Not Twins!)
McGregor said he and Winstead "instantly" clicked while shooting the season, noting that they oftentimes "wouldn't need to run lines" before shooting a scene.
"We just felt it," he remarked of their chemistry on camera.
"This cast is extraordinary with Mary Elizabeth Winstead, David Thewlis and Michael Stuhlbarg and Carrie Coon. We've got some brilliant actors," McGregor told ET. "think this season is quite personal. There is a lot of heart in it and I think that it's going to blow people away."
While the cast was clicking, the same couldn't be said for the bitter Calgary weather, where the show is filmed.
"When we started, it was minus 29 [degrees], so it's brutal up there," he revealed. "But the crew and Calgary are incredibly well-practiced at working in those environments."
Meanwhile, ET also recently spoke to Coon about working with the actor.
"He is as delightful as everyone says," the actress raved. "He just loves working and he's incredibly generous and he's just a very loving person."
WATCH: Kirsten Dunst and Jesse Plemons Are Engaged!
And that shows in his acting.
"Even when he plays somebody who maybe has... some character flaws that we maybe wouldn't agree with, you always root for him no matter what he's doing," she added. "He's playing these two brothers with very different personalities and he's making them very distinct. You just fall in love with both of them and him."
Watch the video below for more of Coon's interview.
Additional reporting by Leanne Aguilera