Her long personal and professional relationship with Gayle King has sparked rumors that they are gay, but Winfrey denies it in an upcoming interview with ABC's Barbara Walters.
Persistent gossip that they are more than good friends annoys Winfrey, she says, explaining that if it were true, "Why would you want to hide it?"
Winfrey will end her daytime talk show next spring and, on Jan. 1, will launch a cable channel, the Oprah Winfrey Network.
That new venture has given her moments of fright.
She tells Walters: "I would wake up in the middle of the night literally like clutching my chest, like, 'What have I done?"'
The interview will air Thursday at 9 p.m. Eastern.