Oprah breaks down while denying lesbian rumours

For 25 years guests have bared their souls on her show, but Winfrey could not maintain her own composure in the face of questions posed by Walters and ended up crying on camera.

"I am not lesbian. I am not even kind of lesbian. I have said we are not gay enough times. That irritates me because it means somebody must think I'm lying. That is not the way I run my life," said the 56-year-old.

Winfrey who has been with long term partner Stedman Graham since 1986, insisted she and King are not involved in a lesbian affair and never have been. "She is the mother I never had. She is the sister everybody would want. She is the friend everyone deserves I don't know a better person. I don't know a better person," said Winfrey about 55-year-old Gayle.

"Shoot, I wasn’t going to cry here. It's making me cry because I'm thinking how much I probably never told her that. I've never told her that," she added sobbing. The interview with ABC host Walters, was to mark the beginning of the end for Winfrey's talk show, which will finish next September after 25 years.

The hour-long special will explore the past 25 years of both Winfrey's personal and professional life, and will also examine her new network, OWN, or the Oprah Winfrey Network, just weeks before its January debut. Asked about family life, Winfrey dismissed the idea of having children because it would not have been compatible with her career.

"For a while I thought, 'Well, maybe,' every time I went to Africa, and Stedman says this too. Every time I went to Africa he didn't know when I got off the plane if I was going to have one or two or ten children," she said.

"I could not have had this life and lived it with the level of intensity that is required to do this show the way it's done. I'd be one of those people that the kid's coming and saying, 'Mom, you've neglected me'. So I have no regrets about that. I have none, not one regret about not having children because I believe that it is the way it's supposed to be," she said.