Kevin Mazur / 1 / 8
Kevin Mazur / 1 / 8

Anna Paquin has come out of the closet.

The "True Blood" star says, "I'm bisexual, and I give a damn," in a new online public service announcement for the Give a Damn campaign, aimed at promoting gay, lesbian, bisexual and transgender equality.

Now 27, Paquin dated actor Kieran Culkin in 2007, and has never discussed her sexuality with the press. She became engaged to "True Blood" co-star Stephen Moyer, 40, in August 2009. The couple hasn't yet announced their wedding date.

"We always take the p--- out of each other and are silly with each other, and it is great," British actor Moyer has said. "We're very, very happy. She's the best."

Launched Thursday, the Give a Damn campaign, featuring Elton John, Whoopi Goldberg, Sharon and Kelly Osbourne, Wanda Sykes and others, is part of singer Cyndi Lauper's True Colors Fund.

"In my life I've crossed paths with many different people and I've seen firsthand what it means to be discriminated against," Lauper says. "As a straight person, I have a responsibility to stand up for gay and transgender people each and every day. We all have to get involved; we all have to give a damn."


More from UsWeekly:

PHOTOS: See Anna and her beau at the 2010 Oscars

PHOTOS: Check out the dress that got Anna on a worst-dressed ever list

PHOTOS: See Anna Paquin's Oscar-winning night -- at age 11!

More on Wonderwall:

Anna Paquin pics

Stars who came out of the closet

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Check out Paquin's announcement