Barbara Walters, Oprah Winfrey Barbara Walters, Oprah Winfrey

Oprah Winfrey is making it clear that she and best friend Gayle King are not gay — and she's sick of the persistent rumors that claim otherwise.

"I'm not a lesbian...I'm not even kind of a lesbian," Winfrey says on Barbara Walters Special: Oprah, The Next Chapter. "And the reason it irritates me is because it means that somebody must think I'm lying ... Why would you want to hide it? That's not the way I run my life."

Winfrey, who has been dating Stedman Graham for 25 years, gets emotional when she tries to explain her deep connection with King.

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"She is the mother I never had," Winfrey tearfully tells Walters. "She is the sister everybody would want. She is the friend that everybody deserves."

Watch the interview below:

Barbara Walters Special: Oprah, The Next Chapter airs Thursday at 9/8c on ABC.