"She likes it, up to a point," Theroux explained. "She'll like it for about a month and then she's like, 'OK, you have to get rid of it.' Then I'm like, 'No, I actually have to keep the beard now for the whole show.'"
Luckily for Theroux, his facial hair gets pretty soft, but he said as it starts to come in, it feels like sandpaper.
"The first season I had to have stubble for the entire season and that was torture for her," he recounted. "[But] now it's soft."
While growing the beard for his show might have been a difficult on Aniston, filming the show all together sounds like it was pretty tough of Theroux.
"I went to the emergency room every single season of this show," the actor said. Trips to the ER stemmed from painful accidents like a broken nose that lead to a slightly deviated septum and a ripped tendon in his middle finger.
Luckily for Theroux's health, this upcoming third season of The Leftovers is also its last, meaning the multi-talented actor/writer/producer is starting to think about his upcoming projects.
Last week, he sat down with ET to open up on his plans for the near future and revealed that he wants to focus on a lot more scriptwriting. He also said that he would "definitely" be interested in writing a TV series that could serve as a vehicle for his wife.
"We toss around ideas occasionally, but it's got to be something I want to write and something she wants to act in," Theroux said. "But yeah, it would be fantastic if we were able to do something together." Check out the video below to hear more.