Michael Douglas - Michael Douglas Explains Cancer Fight

Michael Douglas believes his throat cancer was caused by drinking alcohol.

The Oscar-winning actor - who has two children Dylan, 10, and seven-year-old Carys with wife Catherine Zeta Jones, as well as 31-year-old Cameron with former spouse Diandra - admits his lifestyle has contributed to him contracting the disease, which he says is at an "advanced state."

He said: "I've got cancer. I found out about three weeks ago. It's throat cancer.

"I smoked cigarettes and I drank and this particular type of cancer is caused by alcohol drinking."

The 65-year-old star has begun gruelling radiotherapy and chemotherapy and remains optimistic about his chances of beating the disease - which is at stage four - as it hasn't spread to anywhere else in his body.

He told US TV talk show host David Letterman: "It's intense, and so they've got to go at it.

"You'd like to be down at stage one, but it has not, the big thing you're always worried about is it spreading, I am head and neck, nothing's gone down, and the expectations are good.

"I would hate to say, but right now, it looks like it should be 80 per cent and, with certain hospitals and everything, it does improve."

The actor has also revealed his dad Kirk Douglas joked he should make sure he looked good for his TV appearance.

He said: "I'm on stage. As Kirk would say, 'Son, you gotta look good. You'd never know we might have cancer.'"

However, the 'Wall Street: Money Never Sleeps' star admits he is in pain from the treatment.

He added: "It hurts, it comes and goes in waves. It knocks you out really hard."