Etra said Rihanna will comply with the order. It would mark her first appearance in court since felony assault and criminal threats charges were filed against Brown in March.
If she is called to testify, the 21-year-old singer would be subject to cross-examination by Brown's attorney, Mark Geragos.
Brown was arrested in February on suspicion of hitting and choking Rihanna in a rented car hours before the couple were scheduled to appear at the Grammy Awards.
Etra wouldn't address their relationship now, but said Rihanna, whose real name is Robyn Rihanna Fenty, was following the case closely.
A judge on Thursday rejected a motion by Geragos to receive police and investigative records related to the case and the apparent leak of a photo of a beaten and bruised Rihanna.
Los Angeles Superior Court Judge Patricia Schnegg told Geragos the motion was premature and he could file it again after the preliminary hearing.
Brown wasn't in court Thursday, but he's required to attend the preliminary hearing. The 20-year-old R&B singer faces possible sentences that range from probation to nearly five years in prison if convicted.
Geragos argued that he should have access to the records to properly cross-examine police witnesses during the preliminary hearing. He also said intense public interest in the case should require the records' release.
Schnegg said Brown's fame wasn't an issue she was going to consider. She also called Geragos' motion "a fishing expedition."
She also said the records, which Geragos wants to use to search for police bias or misconduct, don't have anything to do with Brown's arrest. She said officers responded to a 911 call and the "Run It!" singer was arrested well before the photo of Rihanna's battered face was posted by celebrity gossip Web site TMZ.
NEW YORK AND TRI-STATE AREA NEWS
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