Martin Luther King's I Have A Dream speech will be read out by famous rights activists including Malala Yousafzai, the Dalai Lama, Doreen Lawrence and Nelson Mandela's granddaughter, to mark the 50th anniversary of its delivery.
The broadcast, on BBC Radio 4 and the World Service, will mix recordings of the original speech and excerpts spoken by guests.
Listeners will hear the entire speech and there will be contributions from Congressman John Lewis, who was then a civil rights activist and also spoke that day, and singer Joan Baez and writer Maya Angelou.
The speech, in which Doctor King predicted a future where "the sons of former slaves and the sons of former slaveowners will be able to sit down together at the table of brotherhood", was made during a march in Washington DC in support of proposed civil rights legislation.
Radio 4 controller Gwyneth Williams said: "Martin Luther King's words constitute one of the most passionate political statements of the 20th century, a source of inspiration in the quest for freedom in so many different countries around the world.
"I am delighted that Radio 4 is able to bring the whole speech to a global audience for the first time since 1963. I'm also thrilled that we have managed to gather such a distinguished host of contributors to mark the 50th anniversary."
The broadcast will air at 9am on Wednesday and then at 2.30pm on the World Service.