Gabourey Sidibe has never been afraid to take on her haters, and now the actress reveals the source of her confidence.

In a moving speech at last week's Gloria Awards and Gala, hosted by the Ms. Foundation for Women, in New York City, the 30-year-old actress at first declared that she detests questions about how she's so confident.

"One of the first things people usually ask me is, 'Gabourey, how are you so confident?' I hate that," she told the audience during the 80th birthday celebration for Ms. founder Gloria Steinem. "I always wonder if that's the first thing they ask Rihanna when they meet her. 'RiRi! How are you so confident?' Nope. No. No. But me? They ask me with that same incredulous disbelief every single time. 'You seem so confident! How is that?'

Gabourey Sidibe Bites Back at Golden Globes Haters

The Oscar-nominated actress then digressed into a story of how she baked cookies for her fifth-grade holiday party and not a single classmate accepted one.

"I just forgot for a moment that my entire class hated me," she recalled.

They hated her, she said, not just because she was "fat" and "had darker skin and weird hair," but because she was "a snob. I thought I was better than the kids in my class, and I let them know it."

She then returned to the question of her confidence.

Will Gabourey Sidibe's Size Limit her Career?

"Gabourey, how are you so confident?" she said. "It's not easy. It's hard to get dressed up for award shows and red carpets when I know I will be made fun of because of my weight. There's always a big chance if I wear purple, I will be compared to Barney. If I wear white, a frozen turkey. And if I wear red, that pitcher of Kool-Aid that says, 'Oh, yeah!' Twitter will blow up with nasty comments about how the recent earthquake was caused by me running to a hot dog cart or something. And 'Diet or Die?' [She displays her middle finger] This is what I deal with every time I put on a dress. This is what I deal with every time someone takes a picture of me. Sometimes when I'm being interviewed by a fashion reporter, I can see it in her eyes, 'How is she getting away with this? Why is she so confident? How does she deal with that body? Oh my God, I'm going to catch fat!'"

Finally, she revealed the source of that confidence: her Aunt Dorothy Pitman Hughes, whom she described as "a feminist, an activist, and a lifelong friend of Gloria Steinem."

She said every day on the way to and from school, she would pass a photograph of her aunt and Steinem together.

"Side by side they stood, one with long beautiful hair and one with the most beautiful, round, Afro hair I had ever seen, both with their fists held high in the air," Sidibe recounted. "Powerful. Confident. And every day as I would leave the house… I would give that photo a fist right back. And I'd march off into battle."

Mammy to Minnie: Black Oscar Winners

Returning to the story of the fifth grade party, Sidibe said, instead of feeling sorry for herself, she partied her "a** off."

She tied that experience to her current life.

"'How are you so confident?' 'I'm an a**hole!' Okay?," Sidibe revealed. "It's my good time, and my good life, despite what you think of me. I live my life, because I dare. I dare to show up when everyone else might hide their faces and hide their bodies in shame. I show up because I'm an a**hole, and I want to have a good time."

She then thanked her awful fifth-grade class, "because if they hadn't made me cry, I wouldn't be able to cry on cue now," she said, dabbing away tears. "If I hadn't been told I was garbage, I wouldn't have learned how to show people I'm talented. And if everyone had always laughed at my jokes, I wouldn't have figured out how to be so funny. If they hadn't told me I was ugly, I never would have searched for my beauty. And if they hadn't tried to break me down, I wouldn't know that I'm unbreakable ."

Concluded Sidibe, "So when you ask me how I'm so confident, I know what you're really asking me: how could someone like me be confident? Go ask Rihanna, a**hole!

Astrid Stawiarz/Getty Images