The post came just days after the elder Douglas died at age 103.
“Michael joins me in thanking you all for your overwhelming love, kind words and prayers since the passing of my father in law Kirk,” she captioned the photo. “My whole family appreciated every word. Love to you all❤️”
Catherine previously mourned her father-in-law on social media by sharing a black-and-white photo of herself kissing his cheek.
“To my darling Kirk, I shall love you for the rest of my life. I miss you already. Sleep tight…,” she wrote alongside the pic.
Michael also posted a tribute online following his dad’s death, writing in part, “Kirk’s life was well-lived, and he leaves a legacy in film that will endure for generations to come, and a history as a renowned philanthropist who worked to aid the public and bring peace to the planet.”
“I love you so much and I am proud to be your son,” he added.
View this post on Instagram
It is with tremendous sadness that my brothers and I announce that Kirk Douglas left us today at the age of 103. To the world he was a legend, an actor from the golden age of movies who lived well into his golden years, a humanitarian whose commitment to justice and the causes he believed in set a standard for all of us to aspire to. But to me and my brothers Joel and Peter he was simply Dad, to Catherine, a wonderful father-in-law, to his grandchildren and great grandchild their loving grandfather, and to his wife Anne, a wonderful husband. Kirk's life was well lived, and he leaves a legacy in film that will endure for generations to come, and a history as a renowned philanthropist who worked to aid the public and bring peace to the planet. Let me end with the words I told him on his last birthday and which will always remain true. Dad- I love you so much and I am so proud to be your son. #KirkDouglas
On Friday, Kirk was laid to rest at the Pierce Brothers Westwood Village Memorial Park and Mortuary in Los Angeles. Catherine and Michael were in attendance, as was Kirk’s wife of 65 years, Anne Buydens, and his two other sons, Peter and Joel Douglas. Michael’s son, Cameron Douglas, also attended the funeral.