Posting a photo of the two of them on their wedding day, he wrote, "20 Years Ago Today we held hands and walked naively down that aisle. Here’s what I’ve learned since."
He then proceeded with a list:
"Love is Like Gardening... I have learned to focus on HELPING you to BLOSSOM into what YOU want to be (into what you were born to be)... Rather than Demanding that you become what my Fragile Ego needs you to be," he wrote.
"I’ve learned to take pleasure in Nourishing YOUR dreams... Rather than wrestling with you to Fulfill my Selfish Needs & Satiate My Insecurities," he continued.
"I have learned that / Love is Listening. / Love is Giving. / Love is Freedom," he added.
He concluded the New Year's Eve post, which had already garnered over 1 million likes, with, "Happy Anniversary, My Queen! I am forever Devoted to Nurturing your Deepest Truth."
Smith, 49, and Pinkett Smith, 46, tied the knot in 1997. Together they are parents of son Jaden, 19, Willow, 17, and Smith's 25-year-old son from a previous relationship, Trey.
Over the years, they have countered numerous rumors about their relationship, including that they had an open marriage.
In 2013, Pinkett Smith ranted on Facebook, "Will and I BOTH can do WHATEVER we want, because we TRUST each other to do so. This does NOT mean we have an open relationship...this means we have a GROWN one.”
In 2014, she told Net-a-Porter magazine that once she expanded her idea of what a spouse is, her relationship with Smith changed.
"Once I broke all of that, a whole new world opened for me and, man, oh, man, I got to see him in all his glory and so that’s what it’s evolved into," she said. "I’m just ecstatic about it."
In 2016, Smith told an audience during VH1's "Dear Mama" event why he loved his wife so much.
"Jada is magical," he said during the event to celebrate Hollywood moms. "Part of why I love her is things happen in a way they shouldn't happen, they shouldn't go that way. She has this magical power."