By any measure, Oprah Winfrey has accomplished enough in her lifetime. But Winfrey – cultural icon, movie star, media mogul, billionaire – isn’t most people. "I will never be done until my last breath is done," she tells People in their latest cover story. "And whenever that happens it will be a peaceful breath."

As Winfrey nears her 70th birthday next month, she takes stock of her remarkable journey. "Gratitude really is my religion," says Winfrey, whose breakout performance as Sofia in the 1985 Oscar-nominated classic, The Colour Purple "changed everything" for her. "It was a spiritual opening for me to see my life in a different way."

Winfrey begins and ends each day with "Thank you", the touchstone of a cherished practice in gratitude she recommends to everyone. "If you train yourself to do that, you walk through life feeling the abundance instead of the scarcity," she says. "Obviously, people will say, 'Yeah, well, that's easy for you to say, Oprah.' But I've been doing that forever."