The Welsh legend, who was born on 7 June 1940, said he did not mind growing old because "the memories are tremendous".
And he said lockdown reminded him of his own two-year isolation with tuberculosis from the age of 12.
"I sympathise with young people that can't go and play," he said.
Sir Tom, who grew up in Pontypridd, enjoyed huge commercial success with hits including It's Not Unusual, What's New Pussycat? and Kiss.
He became one of the world's biggest stars, with his live Las Vegas performances earning the admiration of Elvis Presley and Frank Sinatra.
