For their latest campaign, the pair posed in matching ripped acid-wash jeans and black crop tops, with "The Real Housewives of Beverly Hills" star trading in her signature hairstyle for a long brunette wig.
Rinna also shared a photo of a billboard that featured the mother-daughter duo posing with the brand's lip kits.
"Our first Rinna Beauty billboard," she wrote.
The reality star's posts were quickly flooded with comments applauding the mother-daughter collaboration and praising Rinna for looking more like Hamlin's "sister" than mom.
"Umm, excuse me? Are you mother and daughter or are you twins? I'm confused. Please share your secret to looking decades younger than you are. PS love the mother-daughter teamwork," one Instagram user commented, while another echoed, "Twinning!"
"Look at them beauties! Rinna, you don't look a day older than 45-years-old," someone else added.
"58 where?!" one fan asked.
"Can't believe she's 58," commented another.
"Cannot wait! Also, how are you so darn beautiful?! You're aging backward, girl!" another commenter wrote.
One fan chimed in, claiming Rinna looked even younger than Hamlin.
"Something is going on — mom looks younger than her daughter," they penned.
Back in 2020, Rinna opened up to Vogue, sharing the secret to her youthful complexion.
“It takes work," she said, adding that "It’s all about maintenance," drinking tons of water, and staying active.
"I truly believe it also starts from the inside, so when I've overdone it, or I've had late nights, I've maybe had a few too many cocktails, my skin will show it," she explained before revealing that she starts every morning with a workout class at 8 am. "It's 45 minutes of joy,"