"Everybody that knows me personally they know I'm gay. But that's the way people should be able to live their lives," she said.
Sykes, who is known for her feisty and blunt style, said the passage of California's Proposition 8 made her feel like she was "attacked."
"Now, I gotta get in their face," she said. "I'm proud to be a woman. I'm proud to be a black woman, and I'm proud to be gay."
Sykes' appearance at the Las Vegas rally surprised organizers. She was in town performing at the Planet Hollywood Resort & Casino.