Michael Douglas, appearing on "The Late Show With David Letterman" on Tuesday, shocked the audience when he revealed his throat cancer is "a Stage IV."

The actor, in town to promote "Wall Street 2," appeared upbeat if a bit thin,after just completing a week of radiation and chemotherapy. He joked with Letterman and, implausibly, managed to keep the interview lighthearted.

Douglas said he found out he had cancer three weeks ago "right when I found out I was gonna be on your show."

"There can't possibly be a medical connection," Letterman quipped.

"It's a Stage IV, which is intense, so they've got to go at it," Douglas told Letterman.

"Now when you said Stage IV, I heard someone gasp," Letterman responded. "Now, is stage 4 where you want to be or where you not want to be?"

"Um, no," Douglas said. "No, you like to be down at stage one."

The 65-year-old said his particular form of cancer is caused by "alcohol and drinking."

"But it has not -- the big thing you're always worried about is it spreading," Douglas continued. "So I am head and neck. I am above the neck, so nothing's gone down, and the expectations are good."

Douglas said his chances of recovery are 80 percent "and with certain hospitals and everything, it does improve.”

"Wow, boy, I feel like I want to do something for you," Letterman said at the end of the interview. "Can I do something for you?"

"Ahh, give me a hug," Douglas said.

They did, and got a standing ovation.