Sage Stallone -- Sylvester Stallone's son -- has died and sources tell us the cause was an overdose of pills.
The details surrounding the death are still unclear .. but we're told he was found in his L.A. apartment by either a maid or his girlfriend. Paramedics were called to the home and pronounced him dead at the scene.
Sources tell us authorities are trying to determine if the death was intentional or accidental.
