Steven Spielberg has matched Brad Pitt’s donation, with both men putting their money where their mouth is.

Steven Spielberg and wife Kate Capshaw have donated US$100,000 to fight Proposition 8 – the proposed amendment to the Californian constitution that would reverse all the lovely marriages we’ve seen lately, and ban gay marriage for good.

“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,” said a joint statement from the celebrity couple this week . “Such discrimination has NO place in California’s constitution, or any other.”

California was the second state in the USA to legalise same-sex marriage. And while at first everything was looking rosy, a backlash against same-sex unions has been flared up, a movement spearheaded by conservatives and religious groups seeking to ‘protect’ the institution of marriage.

Although it appears supporters of the gay marriage ban have raised around $5.5 million more than the likes of Pitt and Spielberg, voters might be swayed more by star-power than the advertising the funds are expected to be spent on. Californian opinion polls indicate most people don’t want to see gay marriage banned.

San Francisco Mayor Gavin Newsom, who allowed same-sex marriage to take place in his city before it was legal throughout the state, is travelling to New York tomorrow for a $5,000-per-person fundraiser to further the pro-gay marriage cause.

The issue of same-sex marriage in California, and fundraising for the campaign has gone nation-wide. Largely because whatever is decided in California in November will have implications for the same-sex marriage debate in the rest of the US, and because the current law in California allows any couple from any state to be married there.

Check out some of the ad campaigns set for release next week