Oprah to wrap up the daytime conversation

But don't panic -- her final appearance as host of "The Oprah Winfrey Show" is nearly two years away. And it's still possible she'll launch another talk show on the cable network she's setting up, called, naturally, the Oprah Winfrey Network.

"The sun will set on the 'Oprah' show as its 25th season draws to a close on September 9, 2011," Winfrey's Harpo Productions President Tim Bennett said in an e-mail to TV station executives Thursday evening, urging them to spread the word.

"As we all know, Oprah's personal comments about this on Friday's live show will mark an historic television moment that we will all be talking about for years to come."

Indeed, the advance notice could turn Friday's show into her most watched ever, beating her previous highest-rated show, on Nov. 15, 1988, when she pulled a wagon filled with 67 pounds of animal fat onto her stage to represent the number of pounds she had lost on a four-month diet.

Not coincidentally, the TV industry is amid the important November ratings derby, which will be used to set ad rates for shows over the next several months. Friday is Oprah's last taping day of her show for the rest of the calendar year.

Although Winfrey's show, like many in syndication, has slid in the ratings over the past few years, this season she's enjoyed a noticeable uptick, thanks to high-profile "gets" that have included the first TV interview with former vice presidential candidate Sarah Palin to launch her book tour. That interview was seen by more than 10 million viewers -- Winfrey's biggest audience since November 2007.

Winfrey also snagged blockbuster interviews such as Mackenzie Phillips revealing she had sex with her father, pop singer John Phillips, for years; the first comeback-album interview with Whitney Houston; and a much-ballyhooed reunion of Mike Tyson and Evander Holyfield.

The show averaged nearly 7 million viewers for the week ending Nov. 8 -- the most recent week for which Nielsen numbers are available.

Word of Winfrey's decision ends months of rampant speculation as to whether she would continue with the five-days-a-week show while finally trying to launch OWN, her long-stalled cable network, in partnership with Silver Spring-based Discovery Communications.

Earlier this month, reports surfaced that Discovery CEO David Zaslav was pressuring Winfrey to move her talk show to OWN. In response to those reports, Harpo issued a statement insisting "she had not made a decision yet," but that one will be made by the end of the year.

Winfrey could not be reached for comment Thursday. Don Halcombe, Harpo Productions spokesman, declined to discuss whether Winfrey was working on a new talk show for OWN, or whether she would take any of that show's more prominent franchises, include Oprah's Book Club, to the cable network, saying only that "she's developing shows for OWN and those are going to reflect her interests and her vision and her values. That could take any number of forms." Halcombe added: "She's also not exclusive to OWN."