“He died of a heart attack this afternoon in a hospital in Cairo,” Steve Kenis, his agent, told ABC News.
Sharif, born Michel Demitri Chalhoub in Alexandria, Egypt, had also been living with Alzheimer's, which was revealed earlier this year.
The news of his ailment broke after Sharif's son gave an interview to Spain's El Mundo, saying "It's difficult to determine what stage it's at. It's obvious he'll never improve and it will get worse."
His son continued, "He still knows he's a famous actor. The loss of memory affects above all specific things," adding that Sharif remembers certain movies he was in, just not things like where it was filmed.
Sharif began acting in the 1950's and went on to star in 1962's "Lawrence of Arabia," earning a Supporting Actor Oscar nod, and "Doctor Zhivago" a few years later. He was a three-time Golden Globe winner and was still being featured in films well into the 2000's after five decades in acting. He starred alongside Viggo Mortensen in 2004's "Hidalgo."
He was also a world-class bridge player and for years wrote a syndicated column about the game.
In 2004, Sharif gave a candid interview with the Guardian, acknowledging that if it wasn't for "Lawrence of Arabia," his life might have been very different.
"What would I be? I would maybe have 10 children ... I don't know," he said.
Sharif was married to Egyptian actress Faten Hamama from 1955 until their divorce in 1974. They had one son.
After the divorce, Sharif never remarried.
"I never fell in love again," he told the Guardian. "I never married, I never lived with a girl."