In the black-and-white snap, the happy couple looked jubilant as they walked arm-in-arm under a series of flowery chandeliers.
The Real Housewives of Beverley Hills star looked almost unrecognisable as she sported a fringe haircut that nearly covered her eyes.
WATCH: Lisa Rinna delights fans in dancing video
Although some stars opt to share lengthy captions with their anniversary photos, Lisa opted for a simpler message, as she wrote: "24 years baby. March 29, 1997."
The star's post was met with an outpouring of love, as Cindy Crawford posted: "Wow – congrats!"
Another fan added: "Love love love love love that those faces are true joy. What a blessing to behold."
A different one said: "That's the Rinna and Hamlin I love," while a fourth posted: "That's truly wonderful! 24 yrs!"
The couple have been married for 24 years
Many other fans simply wished the beautiful couple a happy anniversary.
Although Lisa's marriage to Harry was her first wedding, it was actually Harry's third. The Clash of the Titans star was previously married to actress Laura Johnson from 1985 to 1989 and to actress Nicollette Sheridan from 1991 to 1992.
He was also previously engaged to Ursula Andress, but the engagement was called off in 1983.
The couple have two daughters together, Delilah and Amelia. And earlier this month, the former Days of our Lives actress showcased her eldest daughter's amazing singing voice.
Many fans wished the couple a happy anniversary
In the video, taken from her daughter's TikTok account, Delilah showed off her magical singing voice as she performed To Build a Home.
Just before she began singing, Delilah told viewers: "Hey guys, so I literally just learned this song, and I'm going to play it for you. Like five minutes ago I learned it, so…"
Lisa was full of praise for her daughter, as she gushed: "First Born. Voice of an angel."
She then added an emoji with a halo. And it wasn't just Lisa who was blown away, as many fans were equally wowed by Delilah's angelic singing voice.
"Ummmmmm are u kidding me?!!!! She is a STARRRRRR!" wrote one admiring fan, while another added: "Why did we never know she could sing so beautifully?"
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