Rob Delaney has revealed his 2-year-old son, Henry, died of a brain tumor in January.
The "Catastrophe" star shared the heartbreaking news in an emotional Facebook post on Friday.
"Henry had been diagnosed with a brain tumor in 2016, shortly after his first birthday, following persistent vomiting and weight loss. He had surgery to remove the tumor and further treatment through the early part of 2017," the 41-year-old writer, actor and comedian wrote.
The cancer returned last autumn and Henry lost his battle shortly afterward, explained Delaney, who's married and has two other sons.
"My wife and Henry's older brothers and I are devastated of course. Henry was a joy. He was smart, funny, and mischievous and we had so many wonderful adventures together, particularly after he'd moved home following fifteen months living in hospitals," he wrote.
Henry's disease and the surgery he underwent left him with physical disabilities, wrote Delaney, but his determined young son learned sign language and "developed his own method of getting from A to B shuffling on his beautiful little bum."
"His drive to live and to love and to connect was profound," he marveled.
The London-based star, who often refers to his struggles with clinical depression and addiction in his comedy, added that he was "astonished" by the love Henry's mom and his two brothers were sharing with him and with one another.
"They are why I will endeavor to not go mad with grief. I don't want to miss out on their beautiful lives. I'm greedy for more experiences with them," he wrote.
The actor also shared his gratitude to the medical professionals in England's National Health Service, who, he wrote, "will be my heroes until the day I die."
"I am desperately sad right now, but I can say with authority that there is good in this world," Delaney concluded, before encouraging fans to help other sick children and their families in the United Kingdom by donating to Rainbow Trust and Noah's Ark in Henry's or a loved one's name.
"Thank you, beautiful Henry, for spending as much time with us as you did," Delaney wrote to his late son. "We miss you so much."