Seth Green "shredded" his vocal cords after overworking himself.
The 52-year-old actor suffered a muscular injury to his voice because of doing multiple projects within a two-year period without no rest.
On the latest episode of Josh McBride's The McBride Rewind podcast, Seth explained: "So I, in a 24-month period, was doing Hulk and the Agents of S.M.A.S.H., Family Guy, Robot Chicken, Ninja Turtles, and then I agreed to do Call of Duty.
"I didn’t take care of myself, and I would go from project to project. You need more than a day in between to recover.
"Especially Call of Duty. I did 10 DLC [downloadable content], and each one of them was their own isolated four-hour record."
Seth added that the Call of Duty job was "worse than talking" because of having to repeatedly yell and grunt often.
The entertainer continued: "[My voice was] shredded. And I was doing all of the shows at the same time, and I developed a condition called chondroid metaplasia within my vocal folds."
Explaining the painful condition, Seth said: "Chondroid metaplasia is something that happens in extreme athletes where your muscle is receiving such constant trauma without rehab that it forms cartilage in the place where your muscles formerly were.
"The doctor said, 'Well, you’re a vocal athlete.'
"And then they asked, 'Would you be a cast study? We've literally never seen this before.'
"I was like, 'That's cool.'"
Seth said doctors had to get "scalpels and lasers" to fix the issue, which has made the star to be "definitely better at taking care of myself".
He added: "I don’t have access to my highest registers, but they assured me with practice and time that I could get there."
Seth is best known for playing Scott Evil in the Austin Powers movies, as well as voicing Chris Griffin in the Fox animated sitcom, Family Guy.
Family Guy first aired in 1999, and after it overcame an early cancellation, it has broadcast new episodes since 2005.
The show follows the dysfunctional life of the Griffins - Peter, Stewie and smart dog Brian (all Seth MacFarlane), Lois (Alex Borstein), Chris, and Meg (Mila Kunis) - as they navigate a life full of crazy scenarios.
Family Guy has recently marked its 450th episode.
