Oprah Winfrey set up the school after a request from Nelson Mandela
Oprah Winfrey must defend a defamation case filed against her by the former headmistress of her girls' school in South Africa, a US judge has ruled.
Judge Eduardo Robreno refused to dismiss the legal action on Monday, saying Nomvuho Mzamane had enough evidence to pursue her claim.
The star allegedly made remarks about Mzamane in 2007, after sex abuse complaints arose at the school.
The trial is now set for 29 March in Philadelphia.
The abuse emerged in 2007, when one girl complained she had been fondled while others reported being sworn at, grabbed by the neck, beaten or thrown against a wall.
A former matron at the Oprah Winfrey Leadership Academy was later charged with abusing six students.
Mzamane claims that Winfrey made statements to the press and parents at the time, suggesting she was not trustworthy.
Winfrey's lawyers argued that the remarks reflected her opinions, but the judge ruled they were potentially defamatory as they ascribed "conduct which would render her [Mzamane] unfit for her profession as an educator".
Winfrey's lawyer, William Hangley, declined to comment on the decision and Mzamane's lawyer was not available for comment.
The school was opened in Johannesburg in 2007 at a cost of $40m (£26.3m).
Winfrey pledged to build the academy after a meeting with former South African President Nelson Mandela in 2002, and personally interviewed many of the South African girls from low-income families who applied for the initial 150 places at the school.
The US talk-show host has said she was herself abused as a child and has campaigned against abuse in the US.
She described the abuse charges at her school as one of the most devastating experiences in her life.