O’ No! The end of an era is upon us: After 25 seasons, Oprah Winfrey is bidding farewell to daytime TV.

Harpo Productions has confirmed that The Queen of Talk has decided to end the groundbreaking Oprah Winfrey Show she has helmed since 1985. Oprah began her broadcasting career in Nashville, Tenn., and Baltimore, Md., before relocating to Chicago in 1984 to host WLS-TV’s morning talk show A.M. Chicago. The show was renamed The Oprah Winfrey Show the next year and was nationally-syndicated by 1986.

Oprah will announce news of her departure on Friday. The final episode of The Oprah Winfrey Show is scheduled to air in 2011.

“Tomorrow, Oprah will announce live on ‘The Oprah Winfrey Show’ that she has decided to end what is arguably one of the most popular, influential and enduring programs in television history,” Tim Bennett, the President of Harpo, announced in a letter released to ABC affiliates on Thursday. ” The sun will set on the ‘Oprah’ show as its 25th season draws to a close on September 9, 2011.”

Bennett said he was sending out the letter to keep the affiliates from being surprised at tomorrow’s announcement. And he urged the stations to “share this news this evening with your colleagues and viewers.”

“Before she speaks to her loyal viewers, we wanted to share her decision first with you – our valued partners for more than two decades,” he wrote. “Oprah’s personal comments about this on tomorrow’s live show will mark a historic television moment that we will all be talking about for years to come.”

What will you miss most about Oprah?