The singer could face questioning by Brown's lawyer, Mark Geragos, about her argument with Brown inside a rented Lamborghini on a Hollywood street last February.

Geragos has said he hoped to avoid the spectacle of public testimony, but plea-deal talks failed and California's Supreme Court last week rejected his request to delay the hearing to decide if the case should go to trial.

Brown, 20, entered a "not guilty" plea at an earlier hearing to felony counts of assault and making criminal threats, charges that carry up to four years, eight months in prison if he is convicted.

Daily News:

Sources said Rihanna initially considered reconciliation with Brown.

But the Barbados-born beauty has reportedly moved on to new romantic and career interests in New York.

"Who knows what she'll say? But it's wise for the prosecution to put her on now because if she refuses to testify at trial, they can use her preliminary hearing testimony," said Loyola Law School Prof. Stanley Goldman, a former public defender in Los Angeles County.

Brown's lawyer, Mark Geragos, took his attempt to postpone today's hearing all the way to the California Supreme Court.