Oprah Winfrey has revealed why she agreed to take part in next week’s BBC2 documentary Martin Luther King and the March on Washington.

The film marks the 50th anniversary of the historic March for Jobs and Freedom at which Dr King made his historic ‘I have a dream…’ speech.

In an exclusive interview, Oprah told TV Times magazine: “I wanted to participate because I feel that the march was so valuable to the nation. It changed the trajectory of how black Americans felt about what was possible for ourselves.”

Recently named the ‘world’s most influential woman’, Oprah added, “I was only nine years old at the time so I was too young to march. I just talked in the documentary about my reflections of who I was and where I was at the time.”

Raised in poverty by her grandparents, Oprah, now 59, survived abuse as a a child, and went on to revolutionise Amercian television via a hugely successful daytime chat show made by her own production company.

“I was a kid on the dirt road with the nearest neighbour a mile down the road,” says Oprah, who is reported to have a personal fortune of £500 million, “but from the time I was four years old I always knew that my life would be bigger than that dirt road in Mississippi.”

For the full interview with Oprah Winfrey read this week’s TV Times.