Charles Fawcett, who died in London on February 3 aged 92, was a film maker and adventurer of great and generous passions that embraced Afghan freedom fighters and the much-married film actress Hedy Lamarr.

His unlikely - some would say unbelievable - life was informed by an impulse to stand up for the underdog mixed with a thirst for glamour and adventure. Fawcett charmed everyone he met with tales of swashbuckling intrigue and good deeds.

In 1980, following the Soviet invasion of Afghanistan, he helped film the conflict between the Russian forces and their enemies, the Mujahideen - footage that was pivotal in persuading the United States secretly to arm and fund the tribal warriors fighting the Red Army.

Fawcett's film featured the glamorous, ultra-conservative Texan socialite Joanne Herring, portrayed by Julia Roberts in the current Hollywood blockbuster Charlie Wilson's War. In typical Fawcett style, he had alerted her by sending her a note he had scribbled in crayon on the back of a child's notebook: "Come immediately. Bring film equipment. The world doesn't know what's going on here."

Although aspects of Fawcett's career sometimes seemed to soar to the wilder flights of fancy, he did furnish documentary evidence to support descriptions of his deeds of military derring-do.

After the war he recalled being reduced to playing trumpet at funerals and carrying out exhumations to identify victims of the Nazis. After a friend offered him a bit part in a film, Fawcett spent the next 25 years reinventing himself as an actor, appearing in some 100 B-movies, many made in Italy.

Gossip columnists crowned him "the king of Rome" and "mayor of the Via Veneto", while Warren Beatty recalled him as the hub of the Roman dolce vita, "loved and adored by everyone".

Charles Fernley Fawcett was born on December 2 1915 at Waleska, Georgia, where his mother had been caught in a snowstorm, but came from old Virginia stock. Orphaned by the age of six, he and his younger brother and two sisters were raised by two maiden aunts at Greenville, South Carolina, where he acquired the old-world manners of a typical southern gentleman.

In 1937, having run away from Greenville senior high school, where he had learned to wrestle and to play American football, he made his way to New York and then Washington DC, where a cousin happened to be the US assistant postmaster-general and took him in. By his own account, when he was 15 Fawcett had started an affair with his best friend's mother. "If that's child molestation," he declared, "I would wish this curse on every young boy."

But the end of this adolescent affair had set up suicidal thoughts, and Fawcett jumped a series of tramp steamers, working his passage through the Panama Canal to the Far East before returning to the United States.

Gifted with an artistic talent and a musical ear, he received tips on playing jazz trumpet from Louis Armstrong, and on grappling from a professional wrestler, with the result that Fawcett, still restless, spent a year in eastern Europe earning a living by fighting in back-street theatres.

When the Nazis invaded Poland in 1939 Fawcett joined the Polish army but had been in barracks for only a week before escaping from the advancing Nazis and hitchhiking back to Paris. When the French rejected his application to enlist, Fawcett joined the Section Volontaire des Américains - the ambulance corps.

He was sharing a studio with another young American, Bill Holland, whose mother was a German aristocrat. One of Holland's relatives, General Otto von Stülpnagel, had been appointed commander-in-chief of occupied France, and when Holland introduced Fawcett to senior German officers he was able to pass important information to the French Resistance.

In Paris Fawcett also took part in the rescue of a group of British prisoners-of-war who had been placed under French guard in a hospital ward by the Germans. By impersonating a German ambulance crew, Fawcett and a comrade marched in at 4am and ordered the French nurses to usher the PoWs out into the yard. "Gentlemen," he announced as he drove them away, "consider yourself liberated."

"You're a Yank," said a British voice.

"Never," came Fawcett's lilting southern burr, "confuse a Virginian with a Yankee."

In 1942 he joined the RAF and trained as a Hurricane pilot but was invalided out that Christmas with tuberculosis, from which he had suffered as a youth. After convalescing in a Canadian sanatorium, Fawcett decided to make his way back to the United States.

From New York he travelled to a TB clinic in Arizona where he remained for about a year. In 1944 he returned to Italy and rejoined the American ambulance corps.

For six months in 1945 he fought with the French Foreign Legion in the forests of Alsace, and took part in the liberation of Colmar. A further bout of tuberculosis landed him in the Legionnaires' Hospital in Paris, and although he applied to rejoin his regiment, Fawcett was turned down.

In three months at the end of the war, Fawcett married six Jewish women who had been trapped in concentration camps, a procedure that entitled them to leave France with an automatic American visa.

By 1948 Fawcett was back in action, this time against the Communists in the Greek civil war, fighting in a lounge suit in the guise of a journalist, since no foreigners were supposed to be involved. The following year, he returned to Paris and began his career as an actor, working in the theatre, radio and films. During the next 25 years he appeared in two films with Sophia Loren, knew Orson Welles and William Holden, and in Rome - between two of her six husbands - became the lover of Hedy Lamarr.

In 1956 he spent three months helping to rescue refugees from the Hungarian uprising and, following riots in the Belgian Congo in 1959, joined a friend with a private plane in missions to rescue people who had become trapped and unable to escape the fighting.

Fawcett made his last two films in the mid-1970s, playing the lead in one and in the other, Up The Antique Stairway (1975), supporting Marcello Mastroianni.

Later in the 1970s, short of money and in poor health from a recurrence of tuberculosis, Fawcett accepted an invitation from an old friend, Baron Ricky di Portanova, a wealthy figure in Houston's high society, to supervise the building of a huge new swimming pool complex at his mansion.

Fawcett moved in, and although his new billet afforded access to the best doctors in Houston, he failed to settle. In June 1979, when the Soviets invaded Afghanistan, he announced that he was leaving for that country to pass on to the Afghan resistance fighters tactics he had learned in the Foreign Legion.

Charles Fawcett's first wife died in 1956 and after a 30-year engagement he married, in 1991, April Ducksbury, with whom he settled in London. She survives him with the daughter of his first marriage.