In an interview with AfterEllen, the Pineapple Express star said that GLAAD (Gay And Lesbian Alliance Against Defamation) aided her in her decision to come out.
"GLAAD is one of the many reasons that I, as a 24-year-old, can come out," she said. "I think when I became aware of my role in the media, I had to ask myself an important question, 'Am I part of the problem?'
"And I think that when millions and millions of hard-working, tax-paying Americans are denied their rights and denied their equality, you have to ask yourself what are the factors that are an epidemic problem and that's what this is."
The actress, who stars with Johnny Depp in the upcoming movie The Rum Diary, attended the recent GLAAD 25th anniversary party with partner Van Ree, a photographer and artist.
Of Van Ree, who Heard has been dating since 2008, she said: "She is beautiful. I mean, you'd have to be crazy not to want to go out with her!"