The Oprah Winfrey Show is to close in 2011 after more than two decades on air, the production company behind the programme says.
Winfrey has hosted the show since 1986.
A spokesperson for her Harpo production company would not say why she had made the decision but said she would discuss it on Friday's show, the BBC reports.
Winfrey is expected to focus instead on the launch of her own television channel.
The Oprah Winfrey Show has an average of seven million viewers