Father doesn't know best if your name is Griffin O'Neal.
Griffin -- the son of actor Ryan O'Neal and self-described stepson of the late Farrah Fawcett -- painted his father as an adulterer, opportunist and narcissist on Larry King Live on Monday night.
Griffin, who said he was barred from attending step-mother Farrah Fawcett's funeral, told King that his father was upset with his longtime love, Fawcett, for falling ill because "the attention was diverted to Farrah. He didn't like that ... he's an absolute complete narcissist in every way."
He said that O’Neal’s role in TV specials documenting Fawcett’s illness -- depicting him as a loving, caring mate -- was just a show for the cameras.
Griffin -- who described Ryan as "faithless" -- said Farrah once walked in on the Love Story star getting it on with another woman.
"She walked in on him and he was with some other woman," he said. "I know this for a fact. She told me. He forgot. He locked every lock in the house, except he forgot that she had a remote control for the garage, and there she is."
Fawcett died June 25 in Los Angeles after a long battle with anal cancer.