Sylvester Stallone's son Sage has passed away reportedly from overdosing on pills.

The 36-year-old actor-and-director was found in his Los Angeles apartment by either his girlfriend or a maid on Friday July 13.

The emergency medical personnel were called and when they arrived at the home they pronounced Sage dead at the scene.

Sources claim that police are still trying to determine whether Sage's cause of death was accidental or intentional.

Sylvester is reportedly a "wreck" after hearing the news.

Sage made his movie debut alongside his father in the 1990 film Rocky 5. He played legendary character Rocky's son Robert Balboa in the feature.

He also appeared in 1996 film Daylight. That same year Sage co-founded Grindhouse Releasing, a company that is dedicated to restoring and preserving exploitation movies, with film editor Bob Murawski.

Sylvester's first wife Sasha Czack is mother to Sage.