Michael Douglas, David Letterman

Michael Douglas says he has Stage IV throat cancer, but remained optimistic about a full recovery.

"The percentages are very good. I would hate to say, but right now, it looks like it should be 80 percent, and with certain hospitals and everything, it does improve," Douglas said on The Late Show with David Letterman Tuesday.

Check out photos of Michael Douglas

The Oscar winner, who just finished the first of eight weeks of radiation and chemotherapy, said he was diagnosed three weeks ago ("Just when I found out I was going to be on your show," he joked to Letterman). Douglas said he had a sore throat early in the summer, but doctors did not initially find anything until he returned from vacation with his family.

Michael Douglas to undergo chemo for tumor in throat

Asked about the severity of his condition, Douglas, 65, said, "You'd like to be down at Stage 1," but noted that his cancer has not spread.

"The big thing you're always worried about is it spreading, so I am head and neck," he said. "I am above the neck, so nothing's gone down, and the expectations are good."

Douglas can next be seen in Wall Street: Money Never Sleeps, which hits theaters Sept. 24.

Watch the clip below: