Sylvester Stallone

One month after the death of his son, Sylvester Stallone has opened up about his grief.

While promoting his upcoming film The Expendables 2, Stallone discussed Sage's death on Good Morning America. "It's very, very tough," Stallone said. "It's a horrible situation, but time, hopefully, will heal, and you try to get through it, but it's just something that's a reality of life."

Autopsy on Sage Stallone complete; cause of death still unknown

Sage Stallone, 36, was found dead in his Los Angeles apartment in July. Authorities then said there was no suicide note found or signs of foul play. The cause of death is still unknown.

"It's important to get back and try to start reliving your life; otherwise you can go into a spiral," Stallone added.

Sage starred alongside his father in Rocky V and Daylight and later became a director and producer.