Nov. 20 (Bloomberg) -- Oprah Winfrey announced the end of her TV talk show on the air as she prepares to start a cable channel with Discovery Communications Inc.

The television host informed the audience of her decision to end the show in 2011 at today’s taping in Chicago. Winfrey will host a show and develop programs for the new Oprah Winfrey Network, according to two people with knowledge of the plans.

“The Oprah Winfrey Show,” syndicated by CBS Corp., helped make the 55-year-old entertainer one of the richest Americans, with a net worth of $2.3 billion, according to Forbes magazine. It spawned an empire that includes a magazine as well as film and television production. Winfrey formed a venture in January 2008 to convert Discovery Health into the Oprah Winfrey Network.

“After much prayer and months of careful thought, I’ve decided that next season, the 25th season, will be the last season of the ‘Oprah Winfrey Show,’” she told the audience. “These years with you, our viewers, have enriched my life beyond all measure.”

The last show will be on Friday Sept. 9, 2011, Tim Bennett, president of Harpo, said in a letter to stations that carry the program. Reruns of “The Oprah Winfrey Show” can air on OWN after the program is off the air, said the people, who asked not to be named because they aren’t authorized to speak publicly.

Winfrey also will host a new show on OWN, the people said. The network will begin broadcasting in January 2011 to about 80 million homes, Discovery said today in an e-mailed statement.

CBS Talks

“I think it’s a very gutsy move because obviously there’s a profound difference between producing one compelling show and filling a whole channel with compelling programming,” Christie Hefner, the former chief executive officer of Playboy Enterprises Inc., said today in an interview.

CBS was still in talks with Winfrey this month, CEO Leslie Moonves said on a Nov. 5 conference call. Any effect from the loss of the show won’t be felt until 2012, he said.

“We have the greatest respect for Oprah and wish her nothing but the best in her future endeavors,” New York-based CBS said in an e-mailed statement. “We look forward to working with her for the next several years.”

CBS, owner of the most-watched U.S. broadcast network, fell 47 cents, or 3.5 percent, to $12.84 at 4 p.m. in New York Stock Exchange composite trading. The shares have gained 57 percent this year.

Discovery Communications, based in Silver Spring, Maryland, and part of billionaire John Malone’s cable holdings, rose 4 cents to $31.16 on the Nasdaq Stock Market and has more than doubled this year.

25-Year Run

Winfrey’s talk show is averaging 6.8 million viewers in the TV season that started in September, a 10 percent gain from her average audience in the previous year, according to Nielsen Co. data. Winfrey was averaging 12.6 million viewers in the 1991- 1992 season, the New York-based researcher said.

The show began airing in September 1986, according to the Internet Movie Database, an entertainment industry Web site owned by Amazon.com Inc. When it ends, the program will have been running for 25 years.

“It was absolutely wonderful,” said Ethel Jackson, 55, of Bridgeport, Connecticut, who was attending the show for the first time with three friends. “It was emotional. The tears were definitely there.”

Sue Plochinski, 50, was at the show after her husband gave her a trip to Chicago as a surprise birthday present. It was the second Oprah show for the Detroit resident.

“I cried a lot,” Plochinski said. “I’m happy for her. Twenty-five is a good number.”

“The Oprah Winfrey Show” has remained the highest-rated talk show for 23 straight seasons, winning every sweep since its debut, according to a statement at Oprah.com, which cited Nielsen data. The show airs on 215 U.S. stations and in 147 countries, according to the statement.

Syndicated Shows

In addition to her program, Winfrey also started several successful syndicated talk shows including “The Dr. Oz Show,” “Rachel Ray” and “Dr. Phil,” according to IMDB.com. In September 2006 she started the “Oprah & Friends” channel on satellite radio.

Sony Pictures Television syndicates the show hosted by Dr. Mehmet Oz, a health expert who appeared on Winfrey’s program for three years on a regular basis.

Oprah’s Book Club, a segment in her show, is a premier venue for promoting books. Begun on Sept. 19, 1996, with the selection of Jacquelyn Mitchard’s novel “The Deep End of the Ocean,” a Winfrey endorsement has almost always led to a dramatic boost in a title’s sales.

Winfrey has already had success with a cable channel. In 2007, NBC Universal, the media company controlled by Fairfield, Connecticut-based General Electric Co., paid $925 million for Oxygen Media, a network for women that she co-founded.

To contact the reporter on this story: Andy Fixmer in Los Angeles at afixmer@bloomberg.net

Last Updated: November 20, 2009 16:14 EST