Jerry Lewis, the high prince of low-brow comedy on stage and in movies as well as a fund-raising powerhouse with his annual Labor Day telethon, died on Sunday of "natural causes" at the age of 91, his family said.

"Famed comedian, actor and legendary entertainer Jerry Lewis passed away peacefully today of natural causes at 91 at his home in Las Vegas with his family by his side," a statement from the Lewis family said.

His spokeswoman, Candi Cazau, said by phone that he died around 9:30am PDT (12:30pm EDT/1630 GMT).

Lewis, who rose to fame as goofy foil to suave partner Dean Martin and was a comic icon in France.

He once summed up his career by saying "I've had great success being a total idiot" and said the key was maintaining a certain child-like quality.

"I look at the world through a child's eyes because I'm 9," he told Reuters in a November 2002 interview. "I stayed that way. I made a career out of it. It's a wonderful place to be."

Lewis was 87 when his last movie, "Max Rose," came out in 2013, playing a jazz pianist who questions his marriage after learning his wife of 65 years may have been unfaithful.

The son of vaudeville entertainers, Lewis became a star in the early 1950s as Martin's spastic sidekick in nightclubs, on television and in 16 movies. At their height, they set off the kind of fan hysteria that once surrounded Frank Sinatra and the Beatles.

Their decade-long partnership ended with a bitter split and Lewis went on to star in his own film comedies.

Lewis' movie persona, like the character he created in the act with Martin, varied little from film to film. He was zany and manic, forever squealing, grimacing and flailing his way through situations beyond his control.

He starred in more than 45 films in a career spanning five decades. His cross-eyed antics often drew scorn from critics but he was for a time a box-office hit who commanded one of the biggest salaries in Hollywood.

LEGEND IN FRANCE

Long after his celebrity faded at home, Lewis was wildly popular in France, where he was hailed as "le Roi du Crazy" (the king of crazy) and inducted into the Legion of Honor, France's highest award, in 1984. He received a similar honor in 2006.

He explained his popularity in France, by saying: "The French are very visually oriented even though they are cerebral. They enjoy what they see and laugh. Then, later, they ask why."

Lewis acknowledged that he elicited either love or hate from audiences -- and little in between.

"When Jerry Lewis is funny on screen, I swear to God I laugh louder than anyone," he said. "... When he's not, he's the worst there is."

Lewis, born Joseph Levitch on March 16, 1926, in Newark, New Jersey, started on upstate New York's Borscht Belt comedy circuit as a singer at age 5.

He first teamed with the debonair Martin in 1946 while they were performing in an Atlantic City, New Jersey, nightclub -- Martin as a singer and Lewis as a comic.

Their largely improvised act, with Lewis making wild comic forays into the audience, was an immediate hit. Their 1950 movie debut, "My Friend Irma," was followed by "My Friend Irma Goes West" the next year.

Their relationship soured, however, and by the time they made their last movie together, "Hollywood or Bust," they reportedly were not speaking. They parted after a 1956 nightclub show, 10 years to the day after they first teamed.

The split reportedly stemmed from personality conflicts and Lewis' interest in producing and directing movies. Others attributed it to Lewis' ego and need for control, as well as a desire for approval from the often-remote Martin.

They reunited in 1976 when Sinatra brought Martin onstage during the muscular dystrophy telethon and they remained friends until Martin's 1995 death.

In 1960, Lewis made his movie directorial debut with "The Bellboy" and starred in the storybook parody "Cinderfella." Three years later, he starred in his most popular movie, the self-directed "Nutty Professor," playing a nerdy academic who makes a potion that turns him into the obnoxiously hip Buddy Love.

TELETHONS

Lewis became closely associated with his annual Labor Day telethon, raising in excess of $2 billion for the fight against muscular dystrophy. He first started doing telethons for the Muscular Dystrophy Association in 1952 before retiring from the job in 2011.

His publicist, Cazau, said on Sunday on CNN that over the years, his telethons had raised $2.45 billion.

Cazau also said Lewis had been planning to make onstage appearances over the next few months, in New York, and in Las Vegas next year.

"He was not a quitter," she said.

Lewis had a movie revival in 1983, winning acclaim as an arrogant talk show host kidnapped by an obsessed fan in "The King of Comedy." He scored another late-career triumph with his 1995 Broadway debut in a revival of "Damn Yankees" and appeared in the film "Funn Bones" that same year.

Lewis was beset for years by numerous ailments, including heart attacks, an inflammatory lung disorder and chronic back pain caused by pratfalls earlier in his career.

Lewis had homes in Las Vegas and San Diego. He had six sons with singer Patti Palmer, including Gary of the rock group Gary Lewis and the Playboys. After a divorce, Lewis married SanDee Pitnick in 1983, with whom he adopted a daughter.