(CNN) A surprise guest appeared at the March for Our Lives in Washington on Saturday to tell the crowd about a dream her grandfather had.

"My grandfather had a dream that his four little children will not be judged by the color of their skin, but by the content of their character," said 9-year-old Yolanda Renee King, the eldest granddaughter of Martin Luther King Jr.

Yolanda Renee King, left, appeared on stage by the side of Stoneman Douglas student Jaclyn Corin at the March for Our Lives.

"I have a dream that enough is enough," King added. "And that this should be a gun-free world, period."

King then led the massive crowd in a chant, cheering, "Spread the word! Have you heard? All across the nation, we are going to be a great generation!"