Sharing some snaps from the shoot, Chrissy - who shares daughter Luna and son Miles with John - wrote on Instagram that she was "10 weeks along and out of my mind happy" at the time.
"I knew the video would take a bit to get together so thought it would be cute to share our news with the world through the ol classic hand on belly trick at the end," she said.
However, just weeks later, she and John were left heartbroken at the end of September (20) following the death of the baby they had named Jack.
"I could have never imagined what would happen over the next 10 weeks...not sure I'll ever be able to watch that video again without sobbing but I hope he feels my tears and knows we miss him so," she continued. "He would have been here any day now - if he were like Luna and Miles, I'd probably be holding him as we speak."
The "Lip Sync Battle" star went on to tell fans she's "so full of regret" that she didn't look at Jack's face when he was born, adding, "I was so scared of seeing him in my nightmares that I forgot about seeing him in my dreams. I hurt every day from that remorse."
Chrissy, who successfully underwent surgery for uterine condition endometriosis on earlier this week (end07Feb21) and is now recovering at home, concluded by saying that she "thought the worst was over," but added, "I guess life and emotions aren't on any sort of schedule. Love you guys to pieces and am grateful for all your support and love. I firmly believe energy and healing travels through the night sky and I feel it, I promise I do. and I love you jack. I miss you so so much."