Chrissy responded with, “Finally, a giggle. Thank you.”
Her comment prompted hundreds of fans to weigh in with words of support, with many saying that the 34-year-old and her musician husband, John Legend, were constantly in their thoughts.
“We love you so much, Chrissy,” one follower wrote.
The Lip Sync Battle star first shared her tragic family news on September 30, shortly after revealing that she’d been hospitalised due to excessive bleeding from her placenta.
“We are shocked and in the kind of deep pain you only hear about, the kind of pain we’ve never felt before,” she wrote in the caption, alongside a gallery of black-and-white photos taken in the delivery room.
“We were never able to stop the bleeding and give our baby the fluids he needed, despite bags and bags of blood transfusions. It just wasn’t enough.”
In one particularly moving image, Chrissy can be seen grieving in her hospital bed, tears streaming down her face. In another, she and John cuddle up to the baby, revelling in their final moments as a family of five. The couple share a daughter Luna, 4, and son, Miles, 2, together.
“Jack worked so hard to be a part of our little family, and he will be, forever,” she continued the post.
"To our Jack - I’m so sorry that the first few moments of your life were met with so many complications, that we couldn’t give you the home you needed to survive. We will always love you."