Sylvester Stallone's son Sage was found dead on Friday at his Los Angeles apartment.
According to gossip site TMZ, "the 36-year-old aspiring filmaker is understood to have overdosed on pills and coroner's officials are investigating if it was accidental or suicide."
Sage's father, movie icon Sylvester Stallone appeared at the Comic Con convention in San Diego on Thursday. He is reported "devestated" and "grief-stricken," according to his publicist.
Sage Moonblood Stallone was the oldest of Sylvester Stallone's children. His mother was Sasha Czack, who was Stallone's first wife. The couple had two sons before divorcing.
Sage Stallone made his acting debut in 1990's Rocky V when he played his father's onscreen son.
According to reports, the now-deceased Stallone was in good spirits recently and the news has come as a shock to family and friends.