"The most amazing, brilliant, beautiful, hilarious, thought provoking, and insightful person I know who continuously lives life out-loud. The future is crazy-bright Girl!" the Sex and the City star began his Instagram caption on November 23, alongside a photo of the pair dressed to impress while posing on the red carpet at the 50th International Emmy Awards.
"None of us ever know where God will guide our paths," Underwood continued, praising Hart for always having his back "since before I even became an actor."
"When a 41-year friendship slaps you in the back of the head and blossoms into romance, you stand up, pay attention, and step forward in gratitude. Gently forward. It begins!" he concluded.
After sharing news of their plans to wed, several of his famous pals showed love and wished the couple happiness and many years together.
"Congrats, friend," Yvette Nicole Brown commented.
Claws actress Niecy Nash added, “Issa fiancé 💍💍💍.”
As we previously reported, Underwood announced his divorce from his wife of 27 years back in May 2021.
- 'Sex And The City' Star Blair Underwood And Wife Désirée DaCosta Announce Divorce After 27 Years Of Marriage
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The exes share three children together, Paris, 25, and Blake, 21, and daughter Brielle, 23, whom they described as "incredible" in their joint breakup statement on social media.
"Three souls to which God entrusted us," the former flames gushed, noting they have "always put their best interests first and will continue to do so."
DaCosta and Underwood said they would continue to be "the best of friends and co-parents," telling fans they will always have the "utmost respect for one another as we embark upon this new chapter of our lives, separately."
Underwood previously credited his then-wife DaCosta with taking on the iconic role of Dr. Robert Leeds on Sex and the City, revealing she urged him to pursue the opportunity.
He's also recognized for starring in TV shows such as L.A. Law, The Event, Agents of S.H.I.E.L.D., and Quantico, in addition to his film work, including Krush Groove, Set It Off, and Something New.