PARIS: To some he was the sexiest man of the 20th century, to others he is an egotistical cad. But as the actor Alain Delon turns 80 on Sunday, France still can’t make up its mind about its greatest screen enigma.

As a slew of new French and Italian television documentaries puzzle over the enigmatic star, even Brigitte Bardot, one of Delon’s oldest friends, has admitted she, too, has never quite solved the riddle.

“You are that eagle with two heads, the ying and the yang, the best and the worst,” the 1960s film icon wrote in a birthday note to Delon.

“You are inaccessible and yet so close, cold yet burning hot.”

The pair claim never to have been lovers despite being the Venus and Apollo of the golden age of French post-war cinema.

Her legend was launched with “And God Created Woman” in 1956, his four years later playing pretty boy killers and mysterious schemers in such classics as “Plein Soleil” — later remade as “The Talented Mr.Ripley” — and Luchino Visconti’s “The Leopard.”

Delon set the template for one of Hollywood’s favorite tropes — the mysterious, cerebral hitman — with his staggering performance as the silent killer in Jean-Pierre Melville’s “Le Samurai” (1967).

Directors from Martin Scorsese and Quentin Tarantino to Jim Jarmusch and Steven Soderbergh as well as Hong Kong’s John Woo all acknowledge their debt to the inner life Delon gave his stylish killer.

The whiff of sulphur that came with that angelic face also proved an irresistible combination to a long line of glamorous actresses who fell for Delon.

All these very public affairs ended in heartbreak, tragedy even in the case of his long and complex relationship with the German actress Romy Schneider — “the love of my life” he has often repeated — who died after taking a mix of alcohol and painkillers in 1982 after her son died in a freak accident, impaled on a railing.

“I was programmed for success, not happiness. The two don’t go together,” said Delon, who lives alone with his dogs in the country near Paris.