The Egyptian cinematic icon's son revealed in an interview with that the 83-year-old actor is struggling with his memory and retired from the industry because of his illness, reported People magazine.
"My father has Alzheimer's. It's difficult to determine what stage it's at. It's obvious he'll never improve and it will get worse," Sharif's son, Tarek El-Sharif, said.
El-Sharif revealed his father confuses the names of his films and has been struggling with the illness for the last three years.
"He still knows he's a famous actor. The loss of memory affects above all specific things, details like when he was in a specific places or who he acted with in a specific film," he added.
He later starred in classics such as "Doctor Zhivago" and "Funny Girl" with Barbara Streisand.