The 41-year-old Game Of Thrones actress, who is already mother to a four-year-old son called Wylie, wrote the blog post titled Daughter for Plan International USA's website - a charity to help children in poverty over the world.
"My daughter will have freedom of choice.
"She will be free to dance, to sing, to be educated in the fields that spark her passion, to marry if she wants, to marry WHO she wants, to remain single, or to fall in love with another woman," she wrote in the emotional post.
Headey wrote that she never expected to be in a position to connect with people, encourage people and help raise much needed awareness.
"Geography dictates my freedom as a woman, geography and the women before us who fought for our equal political voice.
"The inequality that is all too prevalent all over the world is so great and so frightening. We owe it to our sisters who have no voice, and no chance to be heard, to speak up."
Headey went on to say she is expecting her baby girl in six weeks, and she will be able to "wear what she wants, put on lipstick and read books that spark debate."
Headey's pledge is an emotional account showing just how grateful she is that her daughter is going to be born at a time and in a place where she can expect equality on many levels.
Something she admits to not experiencing when she was younger...
We wish all the best to Headey for her baby's birth in a few weeks time.