Rihanna's lawyer said the pop star has been subpoenaed to appear in a Los Angeles court to testify

in the assault case against singer Chris Brown.

Brown, 20, has denied felony charges he beat up and threatened his then-girlfriend Rihanna, 21, during a heated argument last February.

Rihanna's lawyer, Donald Etra, told People.com the recording artist was served in person Tuesday with the subpoena, requiring her to give her side of the story at a scheduled June 22 court hearing.

"Rihanna was served at my office by Los Angeles District Attorney investigators," Etra said. "If the preliminary hearing indeed goes forward, she is now legally required to be there, she will be there, and will answer all questions truthfully."