Jeffrey Dean Morgan's miserable experience playing an alien on "Star Trek: Enterprise" nearly convinced him to quit acting for good.

Long before his breakout roles on "Supernatural" and "Grey's Anatomy," Morgan appeared as a Xindi alien named Damron on the sci-fi series — a job that required extensive prosthetics and left the actor struggling with claustrophobia.

"I hated it so much," Morgan recalled during an appearance on Josh Horowitz's "Happy Sad Confused" podcast. "I was like, 'That's it. I've got to do something else.'"

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Morgan said he sometimes spent 14 hours a day in the prosthetics and had difficulty eating while wearing them.

"I remember I was so claustrophobic," he said. "It just was an experience that I want to forget, and I still wake up sweating about it."

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The experience came during an already tricky period in Morgan's career.

By his mid-30s, he had spent years bouncing between guest appearances, pilots and smaller movies while taking side jobs to pay his bills.

"I was always, always side hustling," Morgan said, recalling that he would build fences and take other jobs that "usually involved hammers."

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Walking away from Hollywood, however, presented its own problem.

"I was like, done, but at the same time I was like, 'What am I going to do?'" Morgan said. "I don't know anything else."

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Morgan said he had reached his mid-30s without an education or an obvious backup career and had begun to believe acting simply wasn't going to work out.

His longtime manager then dropped him, telling him, "You've aged out, bro."

But Morgan's fortunes soon changed dramatically. 

Around age 38, he landed roles on "Supernatural," "Grey's Anatomy" and "Weeds" within roughly the same period — finally getting his breakthrough after years of struggling to stay in the business.

These days, Morgan is still going strong. 

He currently stars as Negan opposite Lauren Cohan's Maggie in the third season of AMC's "The Walking Dead: Dead City," which premiered July 26. Morgan is also an executive producer on the series.