The 'Butch Cassidy and the Sundance Kid' actor has been suffering from the potentially fatal disease for several months and just weeks ago had to pull out of directing a big-screen adaptation of John Steinbeck's book 'Of Mice and Men'.

A friend of the actor - who used to be a chain-smoker - told the National Enquirer magazine: "We have known he is seriously ill for several weeks but his loved ones are being very protective and saying very little."

The legendary actor was reportedly diagnosed with the cancer at the New York's Sloan-Kettering Cancer Center, a few hours drive from his Connecticut home, where he lives with his wife Joanne Woodward.

[dm]