Entertainment Tonight.

Sylvester Stallone's son, Sage Stallone, has been found dead at his home in Los Angeles.

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Sage's attorney George Braunstein confirmed the sad news, telling The New York Post that the 36-year old, "was in good spirits, and working on all kinds of projects" prior to his untimely death. "He was planning on getting married. I am just devastated. He was an extremely wonderful, loving guy. This is a tragedy."

The cause of death is as of yet unknown.

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Sage was among Sylvester's five children, and one of two sons from his first marriage to Sasha Czack.

The young Stallone was an actor, following in his father's footsteps from an early age. Sage made his debut alongside his father in the fifth installment of the Rocky franchise where he played the son of Rocky Balboa. He also appeared with his father in the 1996 film Daylight.

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