The 80-year-old confirmed in a statement that he is suffering from a "very common and treatable form" of the disease, but still aims to reprise his iconic role as JR Ewing in an upcoming reboot of the soap.
"As JR I could get away with anything - bribery, blackmail and adultery," Hagman said, as reported by TV Guide. "But I got caught by cancer. I do want everyone to know that it is a very common and treatable form of cancer.
"I will be receiving treatment while working on the new Dallas series. I could not think of a better place to be than working on a show I love, with people I love. Besides, as we all know, you can't keep JR down."
Hagman is set to begin production on Dallas on Monday (October 17) and will appear in a minimum of four episodes.
Although it is unknown whether Hagman will need to take a break from filming for treatment, sources suggest that he will likely appear for the entire first season in some capacity.
Dallas wraps filming in January and will air in America on TNT in summer 2012.