Oprah Winfrey became emotional -- and even cried -- while talking to Barbara Walters about her long-time best friend Gayle King, all the while denying rumors  the two have been in a gay relationship for years, saying  she's "not lesbian ... not even kinda lesbian. "

Watch the video on Breaking Celebrity News

The clip, which aired on ABC's Good Morning America Wednesday, was part of an hour-long interview the network plans to run with the two broadcasting icons  in a primetime special on Thursday.

CONTROVERSY: Oprah An Unappreciated Prophet, Says Stedman Graham

Asked by Walters about her relationship with King, Winfrey was careful, yet emotional, with her words; after an awkwardly long pause, Winfrey said, "She is .... the mother I never had. She is the sister everyone would  want. She is the friend that everyone deserves.

"I don't know a better person," Winfrey said, breaking into tears. "I don't know a better person.”

Oprah and Other Celebs Attend The Kennedy Honors

Winfrey told Walters she was so emotional her answer "because I'm thinking about how much I've never told her that."

EXCLUSIVE: GL