Winfrey took her Chicago-based talk show to Washington this week in honor of Barack Obama's inauguration as the 44th -- but first black -- President of the United States.
"God bless America," Winfrey said in the episode that aired live Monday afternoon from the Kennedy Center for the Performing Arts. "On this very special Martin Luther King Jr. holiday, I can't think of any place in the world I'd rather be than right here."
"I just feel so much gratitude for my children to be experiencing this," said Moore, the mother of three daughters.
The actress went on to say she and her husband -- actor Ashton Kutcher, who also appeared on Monday's "Oprah" -- had campaigned for Obama in Iowa.
"We got in a mini-van. We drove 500 miles and hit I don't know how many colleges," she said. "Standing up and speaking is one of my greatest fears ... but I felt like if I didn't go and participate to do something... then I wouldn't feel that I had done enough."
will.i.am, Faith Hill, Mary J. Blige and Seal also performed live on the show the new track "America's Song," composed by David Foster, People.com said.