Theroux was asked about the insane media attention he got when the two started dating.
Ever since her relationship with Brad Pitt, Jennifer Aniston's love life has always been a tabloid staple -- and being thrust into that part of the entertainment industry was a bit of a shock for Justin Theroux once they started dating.
In a sneak peek from "Sunday TODAY with Willie Geist," the reporter asked Theroux whether it was "a shock to [his] system" to see "all that attention that you got" when the two became an item and eventually got married.
"Yeah, I think part of me was like, you know, I'm essentially sort of a character actor and a writer, there's not much there," he said, before revealing the "sage" advice he got from another actor.
"Jason Bateman actually once gave me one of the most sage pieces of advice ever when all that was kind of going on," explained Theroux. "And he said, look, in that side of the entertainment industry, a character is about to be born and that character is you, but it's not you. That character is, you know, angry, that character has got a problem, that character is, you know, sweet. It's just this little soap opera that gets written in the margins."
"And he said, and so my advice is, don't follow that guy's storyline," he added. "And it was a good piece of advice because I stuck to it. And that's the only way you can sort of keep sane and all that."
Theroux, 49, and Aniston, 52, confirmed in early 2018 that they separated at the end of 2017, after over six years together. However, despite their split, Theroux revealed in another recent interview that they've "remained friends."
"We don't talk every day, but we call each other," he told Esquire. "We FaceTime. We text. Like it or not, we didn't have that dramatic split, and we love each other. I'm sincere when I say that I cherish our friendship."
"We can not be together and still bring each other joy and friendship," Theroux continued. "Also, she makes me laugh very, very hard. She's a hilarious person. It would be a loss if we weren't in contact, for me personally. And I'd like to think the same for her."
"The Leftovers" star also addressed the report that one of the reasons he and Aniston split was because she wanted to live in Los Angeles, while he wanted to reside in New York.
"That's a narrative that is not true, for the most part," he told Esquire. "Look, people create narratives that make themselves feel better or simplify things for them. That whole 'This person likes rock 'n' roll, that person likes jazz. Of course!' That's just not the case. It's an oversimplification."
In addition to remaining friends themselves, Theroux and Aniston didn't have their mutual friends -- such as celebrity pal Will Arnett -- choose sides after their breakup.
"In a lot of ways, it's kind of seamless," Arnett told Esquire. "It speaks volumes about both of them. When you've been with somebody in that way, you'll always be connected. And it's hats off to them for how much attention they give that, and how important it is to both of them to maintain that love. I think it's really remarkable."
Theroux's full "Sunday TODAY with Willie Geist" interview airs Sunday, April 25.