As the realization sinks in that, after a quarter of a century, Oprah Winfrey will be ending her syndicated talk show Sept. 9, 2011 – a decision she intends to explain on her program Friday – rivals, admirers and industry analysts are chiming in with their reactions.

As with most things Oprah, there’s admiration mixed with a sense of awe.

Martha Stewart, attending Diddy’s 40th birthday bash at New York’s Plaza Hotel Thursday night (the news about Winfrey had broken late that afternoon), pointed out that Oprah was not retiring.

“She’ll do another show,” said the domestic diva, 68. “She’s evolving. She’s fabulous.” Only don’t be so sure. Winfrey, 55, whose current program reaches about 7 million viewers a day, is preparing to start her own cable channel. And while it has been widely rumored that she would bring her program to OWN: The Oprah Winfrey Network, a joint venture with Discovery Communications, on Friday’s Today show, during a news report on Winfrey’s impact on TV, it was said that there will be no Oprah show once she pulls the plug on the current program.

Gayle King’s Reaction

Winfrey’s best friend Gayle King, 54, dismissed any thought of risks involved with something new, and told PEOPLE at the Diddy party, “When you think about it, Oprah Winfrey has been No. 1 every single year since she started.”

King, who is an editor-at-large for O, The Oprah Magazine, and is close to the media queen, said in response to a question that she was not consulted about Winfrey’s move. “This was definitely Oprah’s decision, and Oprah’s decision alone.”

As for any sense of loss Winfrey might feel about her show, King laughed and said, ” I think that Oprah always makes the best decision for herself. I really do. And I have a feeling she will come up with some things to do. She has a very full life … We don’t need to worry about her filling her time, I promise you that! Life is good for her.”

Ellen’s Announcement

For Ellen DeGeneres, who is the cover girl (along with Winfrey) on the December issue of O magazine, the news about Winfrey’s decision was so big that she announced it to her in-studio audience Thursday.

“Hey listen, I’m going to tell you some news you’re going to hear as soon as you go out into the world, when you leave here. Right before I came out here, I got a call from Oprah and she told me that she is announcing that next year will be her last year. It will be her 25th year, and she feels like it’s time for her to stop.”

Putting her own career into perspective, DeGeneres, 51, went on to say, “I don’t think I could be here without her. I think she has blazed a trail … She is an amazing woman.”

In terms of Winfrey’s legacy, “She will always be the Queen of Daytime Television,” said Ellen, “and she also said she is leaving me all of her money. I was like, thanks Oprah, thank you.”

Heartbroken Fans?

In Winfrey’s hometown of Chicago, reaction is bittersweet – even in a Windy City sweet shop.

“Oprah is huge in Chicago,” candy store worker Sara Crane tells the Chicago Tribune. Despite the rumbling that Oprah is planning to uproot from Chicago and settle in Los Angeles, Crane said, “I think it’d be more detrimental if she left Chicago and went to a different city. I think people would be offended.

Still, looking at the big picture, Crane says, “People will support anything Oprah does. She could run for president and probably win.”