Gary Sinise's son, McCanna Anthony “Mac” Sinise, passed away at the age of 33 due to cancer on January 5.

The Apollo 13 star shared the news of his son’s demise in a statement conveyed on his Instagram account.

Gary revealed that Mac was diagnosed with a "very rare cancer" known as Chordoma on August 8, 2018.

He also shared that his son's diagnosis occurred shortly after his wife Moira Harris was diagnosed with stage three breast cancer.

The Forrest Gump star noted that Mac’s disease spread over time and "disabled him more and more as time went on."

He declared that his son went through a series of five spinal surgeries from 2018 to 2020, resulting in paralysis from the chest downwards.

Gary also shared in a statement that his son was also "an exceptional drummer" and he showed his skills in his father's Gary Sinise and the Lt. Dan Band act.

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He noted in his statement, "Like any family experiencing such a loss, we are heartbroken and have been managing as best we can. As parents, it is so difficult losing a child."

Gary added, "My heart goes out to all who have suffered a similar loss, and to anyone who has lost a loved one. We've all experienced it in some way. Over the years I have met so many families of our fallen heroes. It's heartbreaking, and it's just damn hard."