The 70-year-old shared a throwback of the couple posing on a boat by the water dressed all in white while putting on a loved-up display.
Pierce wore a button-down and pants with a gold chain, with his shirt left wide open as he pressed up against his wife, who was dressed in a white knit lace dress with a swimsuit underneath.
Fans loved seeing the romantic shot, with one leaving the comment: "When two intelligent people meet and fall in love, nothing can shake their lives anymore. They are beautiful too… what more can you want."
Another gushed: "So nice to see a couple lasting so long specially this years," while a third added: "So cute together, you are the greatest couple," while Nina Dobrev dropped a few heart-eyed emojis for good measure as well.
Pierce and journalist Keely, 59, have been married for over two decades, tying the knot in 2001 after first meeting in Mexico in 1994.
The latter is also a budding artist just like his dad, on hand to support him when his "So Many Dreams" exhibition took place in Los Angeles in May.
In an interview with Vanity Fair at the time, the family spoke with the outlet about their shared love for the craft and how they supported the Remington Steele star's new adventure.
Paris confessed, though, that his style of painting differs quite wildly from his famous dad's, saying: ""Our painting sessions are different.
"Mine is a little bit more chaotic, and Dad is calm, cool and collected," he said, explaining that they often did enjoy painting together in their garage and giving each other feedback.
"I'm like blasting music and throwing paint around, but when we are together, we rub off on each other. He inspires me to be more thoughtful and be more meditative while I inspire him to be more spontaneous and free flowing," he continued.
"He paints best when he's not overthinking it and just putting the emotion down. He's my biggest art inspiration, honestly."
"I think we need to just be grateful for our blessings," Paris said, speaking about the conversation surrounding nepotism, with Dylan saying they were trying to "pave our own way."
"It's always gonna be there and we got to recognize it," the 21-year-old added. "At the end of the day, we're just grateful to be here. Dylan's an amazing musician and I'm painting right now, so we're figuring it out. Taking it day by day."
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