Anna PaquinAnna Paquin, who is engaged to her 'True Blood' co-star Stephen Moyer, has explained the thinking behind her surprise decision to come out as bisexual in a gay rights public service announcement this April.

"I'm not someone who endlessly talks about her personal life for no reason, but obviously, as someone who identifies as bisexual, those are issues I really care about," she told Zap2it on Tuesday. "It wasn't like it was a big secret. It was just a cause I cared about and privately supported, but not one that I had ever had an opportunity to speak out about in a way that would be useful."

In a year of coming out stories, some more surprising than others (Sean Hayes, Ricky Martin, Chely Wright), Paquin's case casts light on the constantly shifting politics of how we view celebrities and sexuality.