Steven Spielberg and his wife Kate Capshaw have donated $100,000 to the campaign to defeat a proposed constitutional ban on same-sex marriage in California.

Their donation is the latest high-profile contribution to the campaign, as gay marriage advocates seek to narrow a gap in fund-raising. Brad Pitt donated $100,000 to the No on 8 campaign last week, in what was seen as a wakeup call to entertainment industry figures to pony up more money for the fight.

The proposition would restrict marriage to unions between a man and a woman.

Spielberg and Capshaw said in a statement, “By writing discrimination into our state constitution, Proposition 8 seeks to eliminate the right of each and every citizen in our state to marry regardless of sexual orientation. Such discrimination has NO place in California’s constitution, or any other.”

Producer Bruce Cohen, who has been working on the campaign to defeat Proposition 8, said in a statement, “It’s phenomenal that Kate and Steven are affirming their unwavering commitment to equality in such a significant a way. More than 15 years ago, Steven was the first person in Hollywood who I came out to, news which he greeted with his full love and support then and ever since. It is my fervent hope that other entertainment industry leaders will follow the lead of Brad Pitt and the Spielbergs and fight to maintain equal rights for all Californians.”

Although a recent Field Poll shows that the proposition is losing support, and is opposed by a majority of Californians, opponents have been outraised, and worry that gay rights advocates will grow complacent. Yes on 8 supporters have collected almost $16.2 million from groups ranging from Focus on the Family to the Knights of Columbus.

“Support from the entertainment industry is critical to defeating Prop 8. The forces behind this measure are highly-motivated and supported by millions of out-of-state dollars,” said Chad Griffin, political strategist working to defeat the initiative.