Ryan O’Neal is furious at his estranged son for claiming that he cheated on his late girlfriend Farrah Fawcett with her best friend of thirty years, former model Alana Stewart.

Griffin O’Neal — who was barred access to Farrah’s funeral in Los Angeles earlier this month — has accused the actor of sleeping with the former Mrs. Rod Stewart as Farrah lay dying of cancer in a city hospital.

“They were sharing a room together,” Griffin reveals in the new issue of In Touch Weekly.

Griffin recallls an incident when Fawcett’s father, Jim, walked in on the couple in bed together while visiting his sick daughter. “It made Jim uncomfortable, so he packed his bags and went home,”

Farrah’s longtime friend Javier Salazar also backs up the affair claims, describing Ryan and Alana’s relationship in Farrah’s final days as “fishy.”

“Ryan and Alana are a little too cozy with each other….It is raising eyebrows. They both stayed at Farrah’s (home) in the end.”

Earlier this week, Stewart announced that she will publish a diary of her friend’s fatal fight against anal cancer. The book is scheduled for release next month.