Chris Brown -- Shows Up to Court WITH RIHANNA!!!

The most shocking development yet in the Chris Brown probation saga ... HE SHOWED UP TO COURT TODAY WITH RIHANNA!!!!

Brown -- and the woman he was convicted of beating in 2009 -- arrived to the L.A. Courthouse together Wednesday afternoon where Chris faced allegations that he lied about completing his community service.

Rihanna sat quietly in the gallery with Chris' mom as Brown and his lawyer Mark Geragos told the judge the singer did nothing wrong.

As we first reported, prosecutors believe Chris participated in a scheme to DUPE the court by getting Virginia officials to say he completed service at a day care center that he never actually performed.

But today in court, the judge said he needed more time to review all of the evidence presented by the D.A..-- and ordered Brown to meet with his probation officer within 48 hours to discuss the situation.

The judge says he wants to hear from the P.O. after the meeting -- and scheduled the next court hearing for April 5.

Brown and Rihanna left the courtroom arm-in-arm -- and one person on the scene tell us she smiled at the singer and tried to cheer him up as they left the building.

Apparently, it worked ... 'cause Brown was all smiles as he was driven out of the courthouse.