The French president's office says Johnny Hallyday, who packed sports stadiums for decades, has died at age 74. Picture: AP Photo/Jacques Brinon, File

Paris - Johnny Hallyday, a singer known as the "French Elvis" whose cowboy swagger and gravelly voice helped popularise rock 'n roll in his country, has died at 74 after a battle with cancer, the office of the French president said on Wednesday.

"For more than 50 years, he was a vibrant icon," President Emmanuel Macron's office said in a statement.

Hallyday is often credited with sales of more than 100 million albums over the decades. While never earning stardom in the United States, he won a legion of followers in France and elsewhere in the French-speaking world.

"Johnny Hallyday has left us," the singer's wife, Laeticia, said in a statement to Agence France Presse. "I write these words without believing them. But yet, it's true. My man is no longer with us."

It was not immediately clear where Halladay died.

An agent for Hallyday did not immediately return a call or email seeking comment.

Hallyday, who issued his first recording in 1959, had been preparing a new album and stage tour when news of his treatment for respiratory difficulties in a Paris hospital was announced last month.

American newspaper USA Today once dubbed Hallyday "the greatest rock star you never heard of," but in France he was known simply as "Johnny." A walking monument, he had the star power to fill the 80 000-seat Stade de France.

Hallyday's 2011 album "Jamais Seul" went straight to number one, selling 100 000 copies in the first week, despite his reputation for being viewed by younger generations as uncool, or passé.

Hallyday also starred in several movies and used his image, and steely blue eyes, to earn extra revenue from advertisements for sunglasses.

He was something of a contradiction, as a star who forged his career recycling rock gems such as The Animals' version of "House of the Rising Sun" or Jimi Hendrix's "Hey Joe" in a country that has a legal limit on the amount of English music played on the radio. He once claimed to have been born in Oklahoma.

"He introduced a slice of America in our national Pantheon," said the statement from Macron's office.

Born Jean-Philippe Leo Smet in Paris in 1943 to Huguette Clerc and Belgian-born Leon Smet, the young Johnny was raised by his middle-aged aunt Helene Mar after his parents split up.

He spent his early years on the road with his cousins Desta and Menen and their acrobatic dance troupe, and eventually took to the stage himself at the age of 12, singing country songs dressed as a child Davy Crockett.

The defining moment in his career came when he saw Elvis Presley in the film "Loving You", an experience that prompted him to restyle his image, adopting the hip shake that would characterise legions of rock stars on both sides of the Atlantic.

As Johnny Hallyday, he released his first single, "T'aimer Follement" (To Love You Madly), at 16, and then set about bringing his own brand of rock to an avid French youth emerging from the austerity of the post-war era.

His music and wild stage antics sparked rioting and hysteria, and he soon became famed for his hard living and self-destructive streak as much as for his chart-topping albums.

Partying, drugs, alcohol and dark tobacco, the latter apparently adopted on the advice of rock icon Keith Richards, all took their toll, carving out the husky voice and craggy face that were to become his trademark.

In 1965 he married blonde pop star Sylvie Vartan, with whom he had one son, David Hallyday. Their divorce in 1980 was quickly followed by four successive marriages, including one lasting 62 days and two to the same woman, Adeline Blondiau, whom he first wed in 1990 when she was just 19.

His fifth and longest marriage to the 21-year-old Laeticia Boudou in 1996, with whom he adopted two daughters, Joy and Jade, marked the start of a calmer, more stable phase in his personal life.

When he was hospitalised in 2009 for a severe infection after a back operation, it also emerged that, morphine failing to do the trick, he had been plunged into an artificial coma to tackle pain he had sought for weeks to kill with larger than ever amounts of alcohol.

The leather-clad, Harley Davidson-loving rocker remained a hard-working performer and firm favourite with fans.

He also founded a show business dynasty, with his son David following his footsteps into the music world, and his daughter Laura Smet, by third wife Nathalie Baye, becoming an actress.