Sage Stallone, son of Hollywood actor and director Sylvester “Sly” Stallone, has been found dead, according to The New York Post and TMZ reports.

Sage Stallone was reportedly found at his Los Angeles home where it’s reported that Sylvester Stallone is extremely distraught. Sage Moonblood, attorney for the Stallone’s, said that the death came as a complete shock. Sage was 36 years old.

“He was in good spirits, and working on all kinds of projects,” George Braunstein told the paper. “He was planning on getting married. I am just devastated. He was an extremely wonderful, loving guy. This is a tragedy.”

TMZ’s sources claim the cause of death was a prescription drug overdose.

The Post reports that his mother, Sasha Czack, had also been notified of her son’s passing.

Sage Stallone made his acting debut alongside his father in the least successful “Rocky V.” In the Rocky sequel, Rocky Balboa is struggling dealing with no longer being a boxer and eventually takes a hungry rookie under his wings ( portrayed by Tommy Morrison ). Rocky ( Sylvester Stallone ) also deals with his son Robert ( Sage Stallone ), who struggles to win his father’s affection.  He went on to act in a number of films, including most recently “Promises Written in Water” in 2010 (he also appeared in “The Agent,” a short, and in a 2011 television documentary episode on the Rocky films).

Sylvester Stallone was in San Diego, California recently this past Thursday to promote “Expendables 2,” his new film with Arnold Schwarzenegger which opens nationwide August 17, 2012. The actors spoke on a panel in Hall H at Comic-Con.

*UPDATE 7/14/12 11:38PM* In addition, Braunstein tells PEOPLE, although Stallone smoked cigarettes and consumed candy and soda, the 36-year-old never exhibited any signs of drug use or addiction.

“Sage didn’t even drink,” the attorney, who knew the son of Sylvester Stallone socially and professionally for more than 15 years, tells PEOPLE. “There was a report that his room was filled with liquor bottles. Actually, they were empty bottles of Dr. Brown’s Cream Soda.”

“Sage was a really young, very sensitive, and very talented kid,” says Braunstein. “There has been no indication that there was anything wrong in his life.”

Not only did Stallone and business partner Bob Murawsky recently sign a new contract acquiring a new film for their company Grindhouse Releasing, but Sage also had intended to marry his longtime girlfriend in Las Vegas this very weekend.

At this time we here at Enfinity 1 Productions, wish to offer our deepest condolences to the Stallone family and fans of Sage.

More information as it becomes available but for the very latest due stay tuned to TMZ‘s website by clicking here