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Dallas star Larry Hagman received a frightening cancer diagnosis last year, just a few weeks shy of filming the re-launch of the popular series. In the time since, a lot has changed for the 81-year-old TV veteran.

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"I had a bad patch there last year," he tells ET matter-of-factly of his October 2011 throat cancer diagnosis. While it wasn't the first time he'd been plagued by the disease, Hagman reveals co-star Linda Gray's insistence he pursue the vegan lifestyle has changed his life.

"I feel better for it," Hagman raves. "More agile. I mean, if you could call it 'agile' at 81. I'm doing pretty well and I like [the diet]. I'm thriving on it."

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In fact, Old J.R. is doing so well post-treatment (he's completely cancer free), that he feels healthy enough to film another 13 years of episodes for the Dallas reboot.

"I think I could go for a good, long time," boasted Hagman. "I'd be 94 years old. That'd be good."

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Watch the video for more!

And don't forget to mark your calendars. Season two of Dallas premieres January 28, 2013 on TNT.