Los Angeles, Dec 24 (PTI) "Love Story" star Ryan O'Neal died of "congestive heart failure", according to his death certificate.
The cause of death was revealed two weeks after the Hollywood veteran died on December 8 at the age of 82.
The underlying cause was cardiomyopathy, a disease of the heart muscle.
No other cause was listed, reported The Blast website after obtaining the certificate issued by Los Angeles County.
O'Neal was diagnosed with prostate cancer in 2012 and chronic leukemia in 2001.
His credits included an Oscar-nominated role in the 1970 romantic tragedy "Love Story" and starred in "What's Up Doc?" and "The Main Event" with Barbra Streisand. He also featured in the 1973 comedy "Paper Moon" with his daughter Tatum O'Neal.
O'Neal also starred in the Fox crime drama "Bones" as a recurring character.
He is buried at Pierce Brothers Westwood Village Memorial Park near University of California, Los Angeles.