Actor Michael Brockman, who is a partner in Newman’s race team, said yesterday: “He’s going for a test run to see how it goes.

“But he’s talking about another competitive race. He’s doing better than he was, so why not? Motor sport has always been one of the great loves of his life.”

The 83-year-old Butch Cassidy star, a former chain smoker, looked tired and gaunt when he attended last month’s Indianapolis 500 as a spectator.

Yesterday, however, his actor friend James Naughton said: “As far as I can tell, he’s feeling quite well at the moment.”

The double Oscar-winning star fell in love with the race track after starring opposite his wife Joanne Woodward in the 1969 film Winning.

He entered his first professional race three years later and in 1979 finished second in the gruelling 24-hour Le Mans classic. In 1995, aged 70, Newman astounded the sport by becoming the oldest driver to be part of a winning team in a top American race.

Last night a senior Hollywood executive said: “It is typical of the man that, even having been diagnosed with cancer, he wants to push himself in the sport he adores.

“He is and always will be a winner.”