Talk show host Oprah Winfrey is expected to spend two weeks in Philadelphia defending a defamation case linked to a sex-abuse scandal at her South African girls' school. The trial is set to start March 29. Winfrey's lawyers say in recent filings she must attend as a named defendant and has rearranged her TV production schedule to do so. She also appears likely to testify. The case centers on remarks Winfrey made in suspending a headmistress amid the 2007 abuse complaints. Winfrey had said she “lost confidence” in Nomvuyo Mzamane and was “cleaning house from top to bottom.” A judge this week refused to drop Mzamane's defamation suit. A dorm matron was later charged with abusing six students.