Michael Douglas has a tumour in his throat and will undergo radiation and chemotherapy.
The Academy Award-winning actor's treatment is scheduled to last eight weeks.
Sixty-five-year-old Michael, married to Welsh actress Catherine Zeta Jones, says he expects to make a full recovery.
He told People magazine in a statement he's "very optimistic". His publicist's assistant Eli Barach confirmed his condition to The Associated Press.
The actor won an Oscar for Wall Street and appears this fall in the sequel, Wall Street: Money Never Sleeps.
Michael is currently outside the US, publicist Allen Burry said. He refused to give his location or say where he would be treated.
Douglas and wife Catherine bought a house on Bermuda nearly a decade ago and Zeta-Jones said they planned to raise their two children there.
© Press association