American actor Ryan O'Neal, widely recognized for his Oscar-nominated performance in the 1970 romance Love Story, has passed away at the age of 82, as announced by his son.

The family has not disclosed the cause of death, but O'Neal had been battling chronic leukemia since 2001 and prostate cancer since 2012.

Renowned for his roles in 1970s hits such as What's Up, Doc?, Paper Moon, and A Bridge Too Far, O'Neal's son described him as "a Hollywood legend. Full stop."

"My dad passed away peacefully today, with his loving team by his side supporting him," wrote Patrick O'Neal on Instagram. He added that his father had always been his hero.

O'Neal's rugged good looks propelled him from television soap to movie stardom in the tearjerker Love Story, where he starred as an upper-crust Harvard undergraduate who falls in love with a working-class student, played by Ali MacGraw.

The film is considered by the American Film Institute to be among the top 10 most romantic movies of all time.

Following Love Story, O'Neal starred in the 1972 screwball comedy What's Up, Doc?, alongside Barbra Streisand. He played a Depression-era conman in the road comedy-drama Paper Moon (1973), acting alongside his nine-year-old daughter, Tatum O'Neal, who won an Oscar for her supporting role.

O'Neal also appeared with an all-star cast in the 1977 war epic A Bridge Too Far.

Born in Los Angeles in 1941 to a stage actress mother and a novelist and screenwriter father, O'Neal initially took up boxing in school and later landed small television roles. His breakthrough came with Peyton Place, America's first prime-time soap opera.

Married twice, first to American actress Joanna Moore, with whom he had two children, including Tatum, and later to Emmy-winning actress Leigh Taylor-Young, with whom he had one son, Patrick.

O'Neal was also known for his long-term, tumultuous romance with actress Farrah Fawcett, lasting from 1979 to 1997 and resuming from 2001 until Fawcett's death in 2009.

In a 2011 interview with Piers Morgan, O'Neal expressed how re-watching Love Story "upsets me, actually." Reflecting on his life, he said, "I lost Farrah to cancer, and I just wonder [why] that played out that way for me."

In a tribute to his father, Patrick O'Neal described him as "skilled at his craft, worked so hard, and just loved acting plain and simple." He added, "As a human being, my father was as generous as they come. And the funniest person in any room. And the most handsome clearly, but also the most charming. Lethal combo."

Patrick also paid tribute to Fawcett, his father's long-time love. "Now they meet again. Farrah and Ryan. He has missed her terribly. What an embrace that must be. Together again."