Oprah Winfrey agreed to host or star in a show on her new network and Discovery Communications Inc., her partner in the venture, boosted its funding by 89 percent after costs to start the channel rose more than anticipated.

Discovery will increase the funding commitment toward the Oprah Winfrey Network to $189 million from $100 million, through a loan and debt financing, according to a regulatory filing today. The channel will start on or before Jan. 1, the company said.

The new show will join a lineup of 17 programs announced by the network, which will reach about 80 million homes. Discovery Chief Financial Officer Brad Singer said on a Aug. 3 conference call that the company had spent $75 million on the venture and the total cost would likely increase because of a late start. The network was originally scheduled to begin in 2009.

Winfrey can't host a talk show on her network until the fall of 2011 because of obligations to her broadcast program, syndicated by CBS Corp., Discovery has said. The last episode of "The Oprah Winfrey Show," which helped make the entertainer one of the richest Americans, will air on Sept. 9, 2011.

The TV host is scheduled to appear in other shows on her future cable channel, including "Oprah Presents: Master Class," featuring life lessons from personalities such as former "American Idol" judge Simon Cowell.

Winfrey, 56, will also appear in "Behind the Scenes," about the final season of her syndicated program, Peter Liguori, Discovery's chief operating officer, said on the Aug. 3 call. The network has also signed Rosie O'Donnell, 48, as host of a one-hour daytime program that will begin airing next year.

Discovery, based in Silver Spring, Maryland, rose 1 cent to $37.37 at 9:58 a.m. New York time in Nasdaq Stock Market trading. The Class A shares had gained 22 percent this year before today.

With assistance by Ronald Grover in Los Angeles. Editors: Cécile Daurat, Steve Walsh.