In an interview with Extra at WonderCon, the 32-year-old said he was going to "sit a season out," confirming his absence from the upcoming season.
Last year, Peters opened up to GQ about feeling "exhausted" by sinister roles like the ones he plays on AHS.
"It's just exhausting. It's really mentally draining, and you don't want to go to those places ever in your life," he told the magazine. "And so you have to go there for the scenes, and it ends up integrating it somehow into your life. You're in traffic and you find yourself screaming and you're like, 'What the hell? This isn't who I am.'"
More recently, the actor talked to GQ Style about that interview and what he was feeling when he said that, and he said he planned to "take a break."
"I think it was a full-on burnout," he said. "I'm going to take a break, regroup, decompress, get back in touch with what I feel like I want to do. Not that I didn't want to do any of those roles – they're exactly what I wanted to do. It was just zero to 100 instantaneously. I want to play music."
Official details are unclear as to why Peters won't be appearing in season 9. Other details about the season, including the theme, are sparse, although Emma Roberts is confirmed to return, with Olympian Gus Kenworthy playing her boyfriend.
Roberts and Peters, who started dating in 2012 and got engaged in 2013 — although they took months-long breaks in their relationship in 2015 and 2016 — recently called it quits for good, with Roberts moving on with Triple Frontier actor Garrett Hedlund.
"Emma and Evan were heading for a split and now are just friends," a source told Us Weekly last month. "Evan has moved out. It wasn't a bad breakup."
Meanwhile, Roberts, 28, and Hedlund, 34, were spotted walking together in the Silverlake neighborhood of Los Angeles. Hedlund "had his arm around [her] for a bit and then they were holding hands," a source said.
Another source said Roberts and Hedlund started out as friends. "Garrett and Emma have been friends, but this is new, casual, and just a couple of weeks old," the insider said at the time.
FX renewed AHS through season 10, and during a panel at the 2019 Television Critics Association winter press tour said the drama isn't going anywhere.
When asked how long the anthology series will survive, FX Networks CEO John Landgraf told Deadline that it's "up to Ryan Murphy. It's up to how long he wants to keep going and how many years he has inspired ideas."
Although American Horror Story has been renewed for its ninth season, no premiere date has been announced.