Reverand Jesse Jackson has paid tribute to his friend, Martin Luther King, on the anniversary of his iconic 'I have a dream' speech.

The former Democratic candidate spoke to Newstalk's Breakfast this morning.

He told the show that Dr King's speech - or at least the famous section of it - was ad-libbed, though it was a theme he had spoken on before.

In a radio tribute to the civil rights activist, Reverand Jackson said he himself could never have become involved in politics without him, and President Barack Obama owed his opportunity as leader of the US to Dr. King.

He described the famous speech, which came at the end of a day's marching on Washington, as the 'fulfilling moment when forces came together to preach and hope' after nine years of protest.