Rihanna will take the stand to testify against ex Chris Brown, who faces felony charges for allegedly beating her in February.

"By prearrangement with the District Attorney, Rihanna was served Tuesday June 9, 2009, at my office with a subpoena to appear at the preliminary hearing, scheduled for June 22, 2009," her lawyer, Donald Etra, tells Entertainment Tonight.

See photos of star at court.

"If that hearing does go forward, Rihanna will appear and will answer all questions posed to her by the District Attorney and Mark Geragos, Chris Brown's lawyer," continues Etra.

Look back at Chris and Rihanna's happier days.

Etra has told Usmagazine.com Rihanna would testify if "the law requires."

In April, Brown, 20, pleaded not guilty to one count of assault and one count of making criminal threats. He was arrested on the morning of the Grammys in February.

Check out stars' mugshots.

If convicted, he faces anywhere from probation to four years and eight months in state prison.