Also in the snap is Michael's 102-year-old dad, Kirk Douglas, and his wife, Anne Buydens, as well as Kirk's son Joel, 72, his 63-year-old son, Peter, and his wife, Lisa Schoeder, and two of their kids, Kelsey, 27, and Jason, 16.
"#FamilyFirst," Cameron captioned the pic alongside multiple heart emojis.
Kelsey also shared snaps from the family gathering, including a group pic and a selfie with her grandfather, Kirk.
"A table of strong jaw lines, large appetites and a shared love for attention #FAMILY ❤️❤️ (missing a few key players: @tylerdougie @ryandawglas ) - family photos are tough 😴😴😴," Kelsey wrote, referencing her brothers Tyler, 23, and Ryan, 19.
When ET's Nischelle Turner caught up with Michael and Catherine at the Screen Actors Guild Awards back in January, they gushed over each other.
"He is the kindest man I have ever met in my life," Catherine said. "...He is my best friend."
"We have the same birthday, few years apart," Michael quipped in response, referring to their 25-year age difference. "The first time I ever met her I found out we had the same birthday and I told her, 'I’m going to be the father of your children.'"
"I found out she played golf. I melted right there," he added. "She looked straight into my eyes, and that was it."
Watch the video below for more on the Douglas family.