Sylvester Stallone says son's death is "very very tough"

(CBS News) Sylvester Stallone is opening up about his son, Sage, who died on July 13 at age 36.

During an interview, which aired Tuesday on "Good Morning America," the 66-year-old actor said, "It's tough. It's very very tough. It's a horrible situation but, time, hopefully will heal and you try to get through it. It's something that's a reality in life."

Pictures: Sage Stallone
Read more: Sylvester Stallone skips "Expendables 2" promotions

Stallone appeared on ABC's morning show to promote the upcoming movie, "The Expendables 2," which hits theaters Friday. He sat alongside fellow cast members, including Arnold Schwarzenegger, during the segment.

He said that spending some time on work has helped, explaining, "It's important to get back and try to start re-living your life. Otherwise you can go into a spiral."

On Monday, Stallone, his wife and their daughters attended the U.K. premiere of "The Expendables 2" in London. He previously bowed out of promotion for the movie in the U.S.

Stallone's son, who appeared in "Rocky V," died at his Los Angeles-area home. The cause of death is not yet known.