SCREEN idol Omar Sharif has Alzheimer's.

The 83-year-old has begun confusing fans who ask him for autographs with friends whose names he has forgotten.

And, according to his son, Tarek El-Sharif, the star of Lawrence of Arabia and Doctor Zhivago struggles to remember his great roles.

Mr El-Sharif, who has a small part as a young Yuri Zhivago in the 1965 hit, said his father has not recognised the illness.

He told Madrid daily El Mundo: "My father has Alzheimer's.

"It's obvious it will get worse. There are times of the day when he's better and others in which he feels confused.

"He knows who he is but not necessarily the reason people greet him.

"When someone sees him in the street and approaches him, he often thinks it's someone he used to know who he's forgotten. Most of the time it's a fan.

"The loss of memory affects details like when he was in a certain place or who he acted with in a film.

"He remembers Doctor Zhivago but he's forgotten when it was filmed.

"He can talk about the film but he forgets its name or he calls it something else instead like 'Lawrence of Arabia'."

Mr Sharif senior is understood to be living in hotels in his native Egypt. He is thought currently be staying in a Red Sea resort but rarely leaves his room.

His last role, in 2009, was as a Alzheimer's suffered for a French film called I Forgot to Tell You. But he is not understood to be ready to accept he has now developed the illness himself.

In a 2013 interview, he admitted he was forgetful but a spokesman dismissed suggestions he had the disease as "mere lies".

Mr Sharif was married to Tarek El-Sharif's mother, actress Faten Hamama, for 20 years until 1974. He converted to Islam to marry her and has said she was the love of his life. He does not appear to know she has died, Mr El-Sharif said.