The actor and filmmaker was found dead in his home in Los Angeles Friday by his housekeeper, Sage's attorney, George Braunstein, confirmed to E! News.
Braunstein said friends and family were having trouble reaching Sage, so his mother called Sage's housekeeper, and the housekeeper discovered the body.
But that wasn't as long as three or four days, as some reports have suggested, according to Braunstein, who said Sage uploaded photos to his Facebook page "around 17 hours before his body was discovered."
Meanwhile, investigators are still looking into the exact cause of Sage's passing.
Police officials told E! News there were no signs of forced entry at the home, and no apparent foul play or criminal activity appeared to be involved.
And a coroner's office source said that prescription bottles were recovered in the investigation, but would not say whether they had a role in Sage's death, according to KNBC.
Braunstein said Sage's passing was a shock to all who knew him, and reports that he may have overdosed are even more surprising.
"He was very creative, energetic and very full of life," Braunstein told E! News. "We were just joking about how he was going to get married and have a fun marriage. There was nothing dark or depressing, no problems, certainly no financial problems."
So, just who was Sage Stallone?
Sylvester Stallone's oldest son—the first of two sons from Sylvester's marriage to his first wife Sasha Czack, he made his acting debut alongside his father in Rocky V, playing Rocky Balboa's son.
And although he went on to appear with his father in 1996's Daylight and numerous independent films afterwards, he also worked behind the camera, co-founding Grindhouse Releasing with film editor Bob Murawski in 1996 (a company dedicated to the preservation of exploitation films) and directing the 2006 short film Vic, which screened at the Palm Springs International Festival of Short Films.
In an interview with People in 1996, Czack said, "[Sage] has said, 'I'm not sure if I'm ever going to be as famous as my dad. Is that all right?' "I tell him, 'As long as you give it your best, that's all that matters.'"
As for Sage's relationship with his father, a source close to the Rocky star told E! News, "They had a good relationship. Sly always includes his kids in his life, he's a real father."
Meanwhile, celebs like Kevin Connolly have tweeted heartfelt messages in the wake of Sage's death.
Sage's funeral will be held at St. Martin of Tours Catholic Church in Brentwood, the same church where he was baptized. The date for the service has not yet been released.
—Additional reporting by Marcus Mulick