Doctor Zhivago star Omar Sharif has died aged 83, his agent confirmed today.

The Hollywood star is understood to have died of a heart attack at a hospital in Cairo, where he was resting after being diagnosed with Alzheimer's disease.

In May it emerged that the Egyptian-born actor had been suffering with the illness and was struggling to remember anything about his hugely successful career.

In a frank interview with Spanish media, Tarek El-Sharif, the only child of the star's marriage to ex-wife Faten Hamama, revealed that his father had started mixing up the names of his best-known films - Doctor Zhivago and Lawrence of Arabia - and often forgot where they were filmed.

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Tragic: Doctor Zhivago star Omar Sharif is understood to have died of a heart attack at a hospital in his native Cairo where he was resting after being diagnosed with Alzheimer's disease.

On-screen success: Born in 1932 the son of a lumber merchant in Egypt's second city Alexandria, Sharif (far right) was nominated for an Academy Award in 1963 for his role as Sherif Ali in 'Lawrence of Arabia'

Known for his charismatic good looks and bridge-playing prowess, Sharif had been resting at his home in Egypt, according to the Los Angeles Times newspaper.

Tributes have been pouring in from across Hollywood, from stars including Spanish actor Antonio Banderas, German director Roland Emmerich, American actor Josh Gad and Game of Thrones star Eugene Simon.

'My great friend Omar Sharif has passed away. I will always miss him,' wrote Antonio Banderas, who starred alongside Sharif in the 1999 film The 13th Warrior, on Twitter.

'He was one of the best.'

He added: 'He was a great storyteller, a loyal friend and a wise spirit.'

Hospital: Security guards stand outside the Behman Hospital in Cairo, where Omar Sharif died today of a heart attack. He was resting at the hospital after being diagnosed with Alzheimer's disease

Roland Emmerich, who directed Independence Day and Godzilla, among others, added: 'Very saddened by the passing of Omar Sharif.

'Blessed that I was able to work with such a legend. Love to the family.'

Broadway actor Josh Gad, best known for voicing OIaf the snowman from Disney's Frozen, tweeted: 'Sad to hear about Omar Sharif. I grew up on Lawrence and Zhivago.

Sorely missed: Tributes for Omar Sharif and his career poured in from across Hollywood, after the news of his death

'A legacy with not one but multiple timeless classics.'

Game of Thrones actor Eugene Simon added: 'RIP Omar Sharif, what extraordinary work you brought the world.'

Formerly named Michel Shalhoub, Sharif was born in 1932 in Egypt's second city Alexandria, the son of a lumber merchant.

He started out in the family's lumber business before moving to London to train at world-renowned acting institution, the Royal Academy of Dramatic Art (RADA).

His big break came when he was cast in the role of Sherif Ali in the 1962 film 'Lawrence of Arabia', alongside Peter O'Toole, for which he was nominated for an Academy Award in 1963.

The actor, fluent in English, Arabic, Spanish, Italian, Greek and French, also won Golden Globes for 'Lawrence of Arabia' and 'Doctor Zhivago.'

Success: The actor, fluent in English, Arabic, Spanish, Italian, Greek and French, won a Golden Globe for his performance in 'Doctor Zhivago' (pictured)

Sharif, who was raised a Roman Catholic but later converted to Islam, started acting in the 1950s and had his most high-profile roles in the 1960s, when he also starred in 'Funny Girl' opposite Barbra Streisand in 1968.

He kept working over the following decades, often in TV movies, while also earning a reputation as one of the world's best known contract bridge players.

Sharif met his wife Faten Hamama, at the time one of the Middle East's most successful female stars, when they were cast together in his debut film, The Blazing Sun in 1954.

They had one son, Tarek, who also appeared in Doctor Zhivago as Yuri, aged eight.

Family: Omar Sharif (right) with his then wife Faten Hamama and his son Tarek, who also appeared in Doctor Zhivago as Yuri, aged eight

But the couple got divorced in 1974 and, despite his reputation as an eligible bachelor, Sharif never remarried, saying he never fell in love with another woman.

Speaking of the actor's illness last month, Sharif's agent Steve Kenis said: 'He was diagnosed with Alzheimer's a while ago,'

'It's a serious disease and he hadn't been been able to take any work for many months,' he added.

The agent confirmed news first reported in May by the Spanish daily El Mundo, which cited the actor's son Tarek.

Mr El-Sharif revealed that while his Egyptian-born father knew he was a famous actor, he had started confusing fans who ask him for autographs for people he used to know.

The revelation follows rumours Oscar-nominated Sharif had quit acting because he could not remember his lines.

Sharif himself admitted in an interview in July 2013 that he tended to forget a lot of things but presented it as a positive because it meant he didn't dwell on the past or future and thought purely of the present.