Maria Shriver wasn't the only person who was kept in the dark by her hubby Arnold Schwarzenegger about his love child. The boy himself never knew his father was nobody but the Terminator, a media report said.

Arnold's mistress Mildred Patty Baena never told the child - now 13 - that the True Lies star was his dad, even though Arnold showered him with gifts and put a down payment on his family's home, the New York Post quoted a source close to Baena's family as saying.

The boy's Bakersfield neighbours said he would even refer to Baena's current beau, Alex Aguiar, as his dad.

"He had no idea" about the truth, the source said.

Schwarzenegger was made to admit to fathering a child out of wedlock this week. Before then, Baena's close family didn't even know who the boy's dad was, including her sister, Miriam Peña.

The family's lack of knowledge was especially shocking since both Peña and Baena's mother, Evelyn Peña, 76, also worked for Arnold. Miriam's family says she still works for Arnold, even after the revelations.

Baena's family is mostly upset with her -- and feels sympathy not for her, but for Shriver.