"Because no one has the right to deny another their life, even though they disagree with it, because everyone has the right to live the life they so desire if it doesn't harm another and because discrimination has no place in America, my vote will be for equality and against Proposition 8," the actor said in a statement.
Political strategist Chad Griffin, who is helping coordinate efforts in the entertainment industry to defeat the controversial initiative, said he is hopeful that the move will prompt others to get involved. He added that Democratic billionaire Ron Burkle has agreed to host a large fundraiser at his home in October to rally the entertainment industry against Prop. 8, which opponents say will take away important benefits such as health insurance and will complicate decision-making related to medical emergencies and other situations in domestic partnerships.
In recent weeks, tens of thousands of dollars -- much of it from outside California -- has been donated to groups on both sides of the issue.
The measure was placed on the ballot after the California Supreme Court invalidated the state's prohibition on same-sex marriage in May.