Arnold Schwarzenegger says the affair he had with his family's longtime housekeeper was "the stupidest thing" he ever did to then-wife Maria Shriver and caused great pain to her and their four children.

"I think it was the stupidest thing I've done in the whole relationship. It was terrible. I inflicted tremendous pain on Maria and unbelievable pain on the kids," Schwarzenegger said of the affair that led to a son who is now 14.

The former Republican governor of California made the comments in an interview with "60 Minutes" scheduled to air Sunday, as the one-time "Mr. Universe" and Hollywood action star tries to rebrand himself and promote his new autobiography, "Total Recall: My Unbelievably True Life Story." CBS aired excerpts of the interview Friday.

After leaving the governor's office in January 2011 following a turbulent seven years, Schwarzenegger, 65, has launched a wholesale effort to redeem his reputation in the wake of the embarrassing public revelations about the affair he had with Mildred Baena, a housekeeper who reportedly worked for the family for 20 years. Their son, Joseph, was born just days after Schwarzenegger's youngest child with Shriver.

Baena listed her former husband as the father on the birth certificate and has said she did not know for certain who the father was until the boy began looking more and more like Schwarzenegger.

Revelations about the affair came shortly after Schwarzenegger's political reputation had taken a blow because of a decision made in his final hours in office.

Schwarzenegger commuted the voluntary manslaughter sentence of the son of a political ally. Schwarzenegger said he thought the 16-year sentence for Esteban Nunez was excessive and cut it to seven, but later acknowledged he was helping a friend, former state Assembly Speaker Fabian Nunez.

Esteban Nunez pleaded guilty to voluntary manslaughter in a 2008 attack on an unarmed group of young men after he and some friends were turned away from a fraternity party in San Diego. Three others pleaded guilty to various charges in the stabbing attack that killed 22-year-old college student Luis Santos.

Earlier this month, a Sacramento County Superior Court judge said the commutation was within the powers granted the governor but also criticized Schwarzenegger's action, calling it "an abuse of discretion" and "repugnant to the bulk of the citizenry of this state." The California Republican Party also officially condemned the commutation, saying it was done "without concern for the victims and their suffering."

Schwarzenegger came into office during California's historic 2003 recall election, promising to restore fiscal responsibility to the state. But he faced repeated multibillion-dollar budget deficits that he acknowledged he and lawmakers could not fully address.

The "60 Minutes" interview comes a week after Schwarzenegger launched a think tank at the University of Southern California, the Schwarzenegger Institute for State and Global Policy. He started it in part, he said, because he accomplished only about half of what he set out to do as governor.

Schwarzenegger has also returned to his acting career, appearing most recently in "The Expendables 2" and the forthcoming "The Tomb," co-starring Sylvester Stallone, and "The Last Stand," which opens in January.

Shriver, a member of the politically powerful Kennedy clan, filed for divorce in July. In a separate excerpt of the "60 Minutes" interview released by CBS earlier this week, Schwarzenegger said Shriver has not read his tell-all book.

"I think that Maria is, you know, wishing me well in everything I do," Schwarzenegger told interviewer Lesley Stahl.