Mildred Patricia Baena is the woman with whom former California Gov. Arnold Schwarzenegger fathered a son about 14 years ago, ABC News has learned.
Birth records show Schwarzenegger's son Christopher and his newly revealed child were born less than a week apart.
Known as Patty, Baena reportedly worked in the famliy home as a housekeeper and assistant for more than 20 years, until January.
Amid the public speculation, Schwarzenegger's wife and mother to four of his children, Maria Shriver, was in Chicago Tuesday at the star-studded tribute to Oprah Winfrey, which also featured appearances from Tom Hanks, Tom Cruise, Madonna, and ABC News' Diane Sawyer.
Wearing a glittering blue halter gown, the former first lady of California didn't appear to show any evidence of her recent marital troubles as she paid tribute to her friend Winfrey.
"For more than 30 years you have bestowed upon me the most amazing friendship. You have shown love, support, wisdom, and most of all, the truth …," Shriver said, pausing for a moment after she uttered the phrase "the truth."
Winfrey responded by squeezing Shriver's hand tight, and the audience erupted in applause. People magazine reported that the two dined together on Monday just before the news broke of Schwarzenegger's love child.
Since then a flood of information on the former California governor's extra-marital affair has poured in, while the couple's adult children have publicly reacted to the news.
According to the New York Times, there was a period 14 years ago when Baena was working at the couple's Brentwood mansion while pregnant with Schwarzenegger's child ... at the same time Shriver was also pregnant with Schwarzenegger's son.
Earlier today, two of Shriver and Schwarzenegger's children took to the Internet with reaction to their dad's admission that he fathered a child with one of their household staff members and hid the secret for years, shattering their 25-year marriage.
"I love my family till death do us apart," Patrick Arnold Schwarzenegger, 17, tweeted.
He also quoted lyrics to a song by hip-hop group Fort Minor that read: "Some days you feel like s*** … some days you want to quit and just be normal for a bit."
Pointedly, he recently changed his Twitter name to Patrick Shriver.
His older sister Katherine Eunice Schwarzenegger, 21, also tweeted (as KSchwarzenegger): "This is definitely not easy but I appreciate your love and support as i begin to heal and move forward in life. I will always love my family!"
They are two of the four kids that Shriver and Schwarzenegger have together.
Earlier on Monday Shriver, 55, appealed for compassion and privacy in breaking her silence on her estranged husband's admission.
"This is a painful and heartbreaking time," Shriver said in a statement. "As a mother, my concern is for the children. I ask for compassion, respect and privacy as my children and I try to rebuild our lives and heal. I will have no further comment."