A Jackson family rep tells us Randy is still at the hospital -- Huntington Memorial in Pasadena -- and she doesn't know how long he'll be there.
The rep says, "He's ok," adding it was a precautionary move.
Randy was in court yesterday for the Conrad Murray hearing.
UPDATE: We're told Randy was not taken by ambulance... he walked into the hospital and is still there for tests.
UPDATE 5:40PM PDT: Doctors are still conducting tests, but we're told Randy may now need to stay in the hospital overnight.