- Drug test was administered in Virginia where Brown was doing community service
- Brown said he had a medical marijuana card for California
- Brown is on probabation for assaulting singer Rihanna in 2009
- His former girlfriend tweeted her support Monday
Singer Chris Brown tested positive for marijuana use and will have a probation violation hearing on Novermber 1, a judge ordered Monday.
Brown is on five years probation for a 2009 assault on his then-girlfriend, singer Rihanna. The positive test occurred in Virginia, Superior Court Judge Patricia Schnegg indicated during Monday's hearing.
She said Brown, 23, had told authorities that he ingested the marijuana in California, where he has a medical marijuana card.
Brown lived in his hometown of Richmond, Virginia, while performing his court-ordered community service.
The judge gave Brown some advice before asking if his mother was present -- she was -- in the court.
"You are not only in the public eye, but you're on probation. And you're on probation to me which means that if you violate any laws or orders, then you're subject to a probation violation," she said. "So you're not an ordinary person who just sits there and does what they want."
Schnegg said the hearing will also determine if Brown violated the travel provisions of his probation. She ordered Brown to see his probation officer in the next three days.
Representatives for Brown didn't immediately respond to CNN's request for comment.
On Monday morning Rihanna tweeted: "I'm praying for you and wishing u the best today!" Brown responded, "Thank u so much."