Singer denies the charges as he appears in LA court
The hip hop star was arrested in LA on 8 February after he allegedly attacked the Umbrella singer, 21, in their rented supercar.
Yesterday, Chris, 19, denied the claims during a brief court appearance in California.
Rihanna, real name Robyn Fenty, is currently in her native Barbados.
Her lawyer Donald Etra has confirmed she would testify if called as a witness.
Chris, who faces five years in prison if found guilty, is due back in court in three weeks.