Sylvester Stallone's son Sage has been found dead in his Los Angeles apartment.
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, according to TMZ.
His action hero father, 66, who was at the Comic Con film convention in San Diego yesterday, is 'devastated' and 'grief-stricken', his publicist said today.
Police said they found the younger Stallone in the home while responding to a 'welfare check', however Sages' lawyer George Braunstein said he was found by a housekeeper.
Friends and acquaintances had become concerned because they hadn't heard from Sage in the past day.
Paramedics were called and pronounced him dead at the scene.
'Sylvester Stallone is devastated and grief-stricken over the sudden loss of his son,' the actor's spokesperson Michelle Bega said in a statement.
'His compassion and thoughts are with Sage's mother, Sasha.' 'He was a very talented and wonderful young man. His loss will be felt forever.'
Braunstein said the death came as a shock, telling the New York Post this afternoon: 'He was in good spirits, and working on all kinds of projects.
'He was planning on getting married. I am just devastated. He was an extremely wonderful, loving guy. This is a tragedy.'
Sage Moonblood Stallone was the oldest of Sylvester Stallone's children and co-starred with his father in two films. He was the first of two sons Stallone had with first wife Sasha Czack.
He made his acting debut in 1990's Rocky V - he played his Stallone's onscreen son - and also appeared with his father in 1996's Daylight.