The woman who had Arnold Schwarzenegger’s secret love child has spoken about the affair, saying her son only learned about a year ago who his father was.

Mildred Baena, former housekeeper to movie star and ex-California governor, has kept a low profile since the revelations of the affair emerged.

In an interview in Hello! magazine, Ms Baena said that when her now 13-year-old son, Joseph, learned who his father was his response was simply: “Cool!”

The mother and son posed for the magazine in one of the first published pictures of Joseph – both with slight smiles. She said she was not initially certain Mr Schwarzenegger was the father but started to see a resemblance in her son as Joseph grew older.

She said Mr Schwarzenegger’s wife, Maria Shriver, also grew suspicious as whispers circulated in the household over the similarities between Joseph and her boss.

Ms Baena said Ms Shriver finally asked “point blank” if the boy was Mr Schwarzenegger’s son, and was “so strong” when faced with the truth.