Actor revealed in 2012 that he had been diagnosed with prostate cancer.

Patrick O’Neal said in a post on Instagram on Friday that his father had passed away peacefully.

“This is the toughest thing I’ve ever had to say but here we go. My dad passed away peacefully today, with his loving team by his side supporting him and loving him as he would us,” O’Neal said, adding that his father “has always been my hero”.

No cause of death was given. O’Neal said in 2012 that he had been diagnosed with prostate cancer, but the prognosis was good.

O’Neal, an amateur boxer-turned-actor, broke into the entrainment business in 1964 when he bagged a role in the prime-time television soap opera Peyton Place.

During the 1970s, O’Neal became known as one of Hollywood’s leading heartthrobs, starring in films including What’s Up, Doc?, Paper Moon, and Barry Lyndon.

O’Neal’s most celebrated turn came in the 1970 romantic drama, Love Story, opposite Ali MacGraw,  for which he received an Oscar nomination for Best Actor.

O’Neal, who was twice divorced, was also known for his decades-long tumultuous romance with late actress Farrah Fawcett.

The couple split in 1997 but reunited a few years later, and he was at Fawcett’s side during her battle with cancer.

O’Neal fathered actors Griffin O’Neal and Tatum O’Neal with his first wife, Joanna Moore,  and had son Patrick with his second wife, Leigh Taylor-Young.