Anna Paquin plays a telepathic vampire on HBO's "True Blood," and now the Oscar winner is showing her true self by coming out as bisexual.

Paquin, who's engaged to her "True Blood" costar Stephen Moyer, makes the announcement in a PSA video promoting the Give a Damn campaign, which features celebrities speaking out for equality.

"I'm Anna Paquin. I'm bisexual and I give a damn," Paquin, 27, says on-camera during a private taping on Jan. 30 in Los Angeles, according to RadarOnline. Sources said they were unaware beforehand that Paquin would make the announcement.

Others who were present at the taping included comedian Margaret Cho and singers Mya and Jason Mraz.

Paquin's PSA comes on behalf of the True Colors Fund, an organization dedicated to earning equal rights for people who are gay, straight, bisexual or transgendered. The organization's "Give A Damn" campaign launches Thursday, with Paquin's spot as the first of several to be unveiled on-line in coming months.

Other major names in the campaign include Kim Kardashian, Elton John, Whoopi Goldberg, Cynthia Nixon, Sharon and Kelly Osbourne, Judith Light, Clay Aiken and Wanda Sykes.