The couple, who has been married for 46 years, has a gay daughter. They are starring in the first statewide commercial urging Californians not take away the right of same-sex couples to marry.
"We have become very deeply committed to the principle that our daughter deserves to be treated with every aspect of her life with the same respect and dignity as her two straight brothers," said Thoron.
The new ad launches what promises to be an expensive battle between gay rights and traditional marriage groups. Each side has already raised at least $10 million through August. The "Yes on Prop 8" side is mobilizing churches and will be ready to hit the airwaves next week.
Recent polls show a shift in attitude toward same-sex marriage in the state.
Eight years ago, 61 percent of California voters approved the same-sex marriage ban. However, a field poll completed in September shows Proposition 8 is losing. 55 percent of voters now say they would not ban same-sex marriage. 38 percent said they would ban such unions. Finally, seven percent were undecided.
Californians get to vote on the proposition again in November. That is because the California Supreme Court ruled earlier this year the state's previous same-sex marriage ban was unconstitutional.
Part of the "Yes" side's strategy will be to depict the high court as a group of rogue justices writing law.
"I think we're entering into a very dangerous time when you have four activist judges in San Francisco who throw out the vote of millions of California voters. I think it sends a dangerous message that your vote doesn't count," said Jennifer Kerns, who supports Proposition 8.
While it is a mild start to the Proposition 8 battle, the tone may not stay that way as Election Day approaches.