Haggis said he was quitting the church after 35 years
Oscar-winning film director Paul Haggis has severed his ties with the Church of Scientology because what he said was the organisation's anti-gay stance.
In a letter, Haggis said he was disappointed by the church's tacit denial of gay rights in the debate over California's gay marriage ban.
Haggis, who directed film Crash, said he could not be a member of a body "where gay-bashing was tolerated".
A Scientology official denied the claim the church was in any way anti-gay.
In the letter to church spokesman Tommy Davis, Haggis criticised the organisation for not rebuffing comments by the Scientology's San Diego branch backing Proposition 8 - a ban on gay marriage in California.
"The church's refusal to denounce the actions of these bigots, hypocrites and homophobes is cowardly. I can think of no other word," Harris said.
The Canadian-born director had been a member of the church for 35 years. His letter, which appeared in a blog, was dated 19 August.
Mr Davis responded by saying Haggis' claims were based on misunderstanding.
"We're all for civil rights and the rights of minorities," Mr Davis said.
"We know what it is to be a minority and have your rights curtailed. We're very vocal in our stance on discrimination against anybody. We take it very seriously," he added.
The Church of Scientology was set up in the United States in 1954 and claims to have more than eight million members worldwide.
The church offers self-improvement on the basis of the writings of the late science-fiction author L Ron Hubbard, who spelled out principles that he called Scientology and Dianetics.
But critics claim it is a fake religion based on making money from its followers.