Getty Images: Chip Somodevilla
WASHINGTON -- Oprah Winfrey, Jamie Foxx and Forest Whitaker are among the celebrities joining three presidents this week to mark the 50th anniversary of the March on Washington.
Soledad O'Brien and Hill Harper will host the "Let Freedom Ring" commemoration of Martin Luther King Jr.'s "I Have a Dream speech on Wednesday.
President Barack Obama and former presidents Bill Clinton and Jimmy Carter are also joining the tribute at the Lincoln Memorial.
Georgia Rep. John Lewis, who spoke at the 1963 March on Washington, will speak at this year's march, along with Winfrey, Foxx and Whitaker.
Winfrey and Whitaker are starring in the movie "The Butler" about a man who served for seven presidents as a White House butler.
Musicians including LeAnn Rimes and BeBe Winans are scheduled to perform.