Schoolgirls who were allegedly abused at Oprah Winfrey's academy in South Africa, will soon testify at an upcoming trial in Philadelphia.

The talk-show host herself will be a witness when the school's former headmistress sues her for defamation.

During a 2007 scandal, in which a dormitory matron was charged with abusing six students, Oprah Winfrey told a TV audience she had lost confidence in headmistress Nomvuyo Mzamane and had decided to "clean house" at the academy.

Mzamane has said she had trouble finding a new job after the Winfrey comments.

The defamation case is expected to last for two-weeks starting March 29th.