Douglas gives Letterman details of his cancer

How did Michael Douglas learn he had throat cancer three weeks ago?

"When I found out I was going to be on your show," he told David Letterman Tuesday night, in his first TV interview since announcing via People Magazine Aug. 16 that he had been diagnosed with the disease.

A joke - of course - but Tuesday night's Letterman interview was not. In unusually detailed and sober fashion, Douglas told a surprised "Late Show" studio audience and host exactly what he is up against. He has eight weeks of chemo and radiation therapy ahead, and when Letterman asked, "did they [the doctors] find it early enough for their liking," Douglas replied, "I sure as -- hope so."

Douglas - improbably enough, on the outset of a promotional swing for "Wall Street" sequel, "Wall Street: Money Never Sleeps," which premieres later this month - told Letterman that he had just begun his treatment. He noted that although his cancer is "stage 4 . . . I am head and neck [and] nothing has gone down [to the lymph nodes lower in his body.] The expectations are good."

Then, another joke: "It will cut into the foreign promotional tour."

Douglas said his throat "had been bothering me for a while . . . In early summer, I had a really sore throat, early in the summer, and I actually went through a litany of doctors and tests and they didn't find anything."

After traveling to Europe with his family, a doctor asked to " 'just take a little clip of that [the tumor.]' And this all happened within three weeks, and got a biopsy and they analyzed it - it's a stage 4, which is intense, and so they've got to go at it . . . "

Letterman ended the interview by asking Douglas whether there was anything he could do for him.

"Aaaahhhh, give me a hug."

They hugged.