Gayle King talks to ET about her best friend Oprah Winfrey leaving her number one talk show, saying she didn't believe the news herself!

While discussing O magazine's December gift guide, Gayle spoke candidly about Oprah's departure -- and how the daytime diva is in good spirits after the announcement. "She's not sad," Gayle says, "it's just that it's the end of an era. I know there will be other things to come."

Being so close, Gayle was of course among the first to know. Oprah has talked about ending the show before so she wasn't sure if this time was serious, saying, "I really didn't believe it myself...until she told the staff...I think everybody was kind of stunned." Only a select few knew before the big announcement. "There were a few people she told ahead of time," Gayle says. "Ellen DeGeneres was one. She started crying when she was talking to Ellen."

Gayle is quick to say that "The Oprah Winfrey Show" may be coming to an end, but Oprah is here to stay. "She's certainly not riding off into the sunset," she says.

The Oprah Winfrey Network (OWN) stars January 2011.

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