2ND UPDATE: Two of Arnold Schwarzenegger and Maria Shriver's children have weighed in on the scandal via Twitter (what else?). Patrick Schwarzenegger tweeted: "some days you feel like sh*t, some days you want to quit and just be normal for a bit, yet i love my family till death do us apart."
Older sister Katherine, meanwhile, took to the micro-blogging platform to tweet: "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!"
The couple have four children.
UPDATE: Maria Shriver released the following statement: "This is a painful and heartbreaking time. 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."
EARLIER: Arnold Schwarzenegger fathered a child with a member of his household staff, the reason for Maria Shriver’s decision to leave him, the actor and ex-governor of California said.
"After leaving the governor's office I told my wife about this event, which occurred over a decade ago," Schwarzenegger told the Los Angeles Times on Monday night in response to their questions.
Shriver left Schwarzenegger earlier this year after nearly 25 years of marriage, a bombshell that shocked their friends and many who knew them around the country. The news broke this month.
Schwarzenegger added: "I understand and deserve the feelings of anger and disappointment among my friends and family. There are no excuses and I take full responsibility for the hurt I have caused. I have apologized to Maria, my children and my family. I am truly sorry.”
The household staffer worked for the family for 20 years, according to the paper. Schwarzenegger had been supporting the child previously.
Schwarzenegger and Shriver have long been one of the nation's premier power couples, influential in Hollywood, politics and on numerous social issues -- from health and wellness, to women's concerns -- despite standing on different sides of the political spectrum.
Schwarzenegger is a centrist Republican, while Shriver hails from the liberal Kennedy clan and was an early Obama supporter. They have also dealt with rumors of his infidelity before, and yet his wife had stood by him in those moments.
The news was sure to be a further shock to Hollywood and the world of California politics. The couple have four children. Since leaving office, Schwarzenegger has turned back to several movie projects, while Shriver -- a former journalist who was an active First Lady of the state -- had not yet defined her new pursuits.
The paper did not reveal the name of the former household staffer who worked for the family for 20 years and retired in January, or the name of the child. The staffer initially denied to the paper that Schwarzenegger was the child's father.
Schwarzenegger's statement concluded: "I ask that the media respect my wife and children through this extremely difficult time. While I deserve your attention and criticism, my family does not. "
Schwarzenegger has faced allegations of sexual harrassment and infidelity many times over his years with Shriver. His wife stood by him throughout.
In the wake of the news of their split, Schwarzenegger has still professed love for his wife. "We both love each other very much," he said just days ago at the Skirball Cultural Center in Los Angeles. "We are very fortunate that we have four extraordinary children and we're taking one day at a time."
Shriver lost both her parents in the past couple of years, two pillars in her life -- Sargent Shriver and Eunice Kennedy Shriver.