She posted the images Thursday on social media and shocked her family.
Rinna's husband, actor Harry Hamlin, commented, "THAT’S MY GIRL!!!" While her daughters, Amelia and Delilah, wrote "WAIT WHAT" and "YOU ARE HOT."
Her fellow "Housewives" castmates Kyle Richards, Dorit Kemsley, and Erika Girardi also reacted to the risque photoshoot.
"OH MY GAWD," Richards, 51, wrote. "Please wear this to the Reunion."
"WHHHAATTT!!!" said Kemsley, 43. "Holy S**T! Damn this is next level."
While, Girardi, 48, commented, "YES YES YES."
The pics were taken by photographer Greg Swales, and the designer, Cowan, chimed in with: "Why wear anything when you look this good?"
A healthy lifestyle has always been a priority for Rinna. She previously told OWN, "For me, staying in shape has always been a part of my life and it’s all about consistency."
"Luckily, I was born with good genes, first and foremost, and I know that, [but] I started working out at a very young age — I played competitive tennis — and I've worked out my whole life," she added.
Rinna loves yoga, cycling, and hiking and breaks a sweat "five-six days a week." In terms of her diet, Rinna told People magazine she calls herself a "dirty vegan."
“I don’t love to use the word diet because if I do, I’ll just want to eat 10 times more,” she explained. “Moderation is key. I’m mostly plant-based — but if I do need to eat some meat, I’ll have it.”