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ET has learned exclusively that arrangements have been made to hold a funeral for Sylvester Stallone's son Sage, who was found dead inside his home on Friday.

The funeral has been set for noon this Saturday, July 21 at St. Martin of Tours Catholic Church in the Brentwood section of Los Angeles followed by a burial at Forest Lawn. There will be a closed casket. In lieu of flowers, Sage's mother Sasha has requested that donations be made to the organization Autism Speaks.

RELATED: New Details in Sage Stallone Death

The body of Sage, 36, was discovered Friday afternoon and an autopsy was conducted over the weekend. The official cause of death won't be determined until toxicology reports are completed in the coming weeks.

Braunstein told ET that Sage had been planning on getting married this past weekend in Las Vegas, but that he wasn't engaged, so it was meant to be a spontaneous event.

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