Credit: Dan Steinberg/AP Photo

Actor Ryan O'Neal is optimistic about the prognosis for his stage 2 prostate cancer recovery.  In an exclusive interview with " Nightline," O'Neal said his cancer, which is not stage 4 as previously reported, was "contained" and he is determined to fight it.

"I have it under control," he told ABC's Juju Chang. "I wasn't prepared for it. I wasn't ready for it. But you never are."

O'Neal, nearly 71, who is known for his roles in the films "Love Story" (1970) and "Paper Moon" (1973), and most recently has a reoccurring role on the TV series "Bones," said when he first learned of his cancer diagnosis, he thought, "Why me?"

"I just sort of chalked it up, you know, to bad luck," he said.

O'Neal also revealed he has skin cancer - a melanoma - on his nose.

"Welcome to Malibu and the sun," he said.

An actor and a trained boxer, O'Neal shared a beach house with actress Farrah Fawcett in Malibu for years during their romantic relationship. O'Neal wrote a memoir about his and Fawcett's love story called "Both of Us: My Life With Farrah," which will be published on May 1. Fawcett died of anal cancer in 2009.

It was Fawcett, he said, who taught him not to give up.

"Farrah taught me that - about fighting it, fight a good fight," he said.

The next step in his prostate cancer treatment, O'Neal said, is cryopathy, a procedure where doctors try to stop the cancer from spreading by freezing the infected tissue to kill off the disease.

Each cancer diagnosis stage represents how advanced the disease has become. According to the National Cancer Institute, stage 2 cancers are usually "locally" advanced, where stage 4 cancers are almost always inoperable or have spread to multiple organs.