He was 83.
The Egypt-born actor's agent Steve Kenis said, "He suffered a heart attack this afternoon in a hospital in Cairo."
Sharif was nominated for Oscar for his role in the David Lean-directed film "Lawrence of Arabia" and went on to win a Golden Globe for his performance. It was his first English language role, after appearing in over 20 Egyptian films.
In May, his son said the star had been suffering from Alzheimer's and retired from the industry because of his illness.
More From This Section
Many people connected Sharif's illness with the passing of the iconic actress last January, saying that after her death he started to fade gradually.
The actor was born in Alexandria, Egypt and first rose to international fame for his role in 1962's "Lawrence of Arabia" starring alongside Peter O'Toole.
Sharif worked less in recent years and his last role was in the 2013 drama "Rock the Casbah". He has one film still to be released: a short called "1001 Inventions and the World of Ibn Al-Haytham".
He was caught on video in 2011 apparently slapping a journalist after she attempted to take a photo with him at the Doha international film festival.
He is survived by his son and two grandsons.