While some KUWTK fans approved of her throwback look, many were confused by her notable change in appearance.
"Am I the only one who didn’t recognise sis for like a good 10 seconds?" said one user.
"Lady Gaga, is that you?" joked another user.
Some compared her to the 90s R&B singer Aaliyah - who passed away in a plane crash in 2001 - while others pointed out that she looked like songstress, Toni Braxton.
"So photoshopped you don’t even look yourself anymore, Kim," said another commenter.
Fans were convinced that she didn't look like the Kim Kardashian they had come to know and love.
One user commented, "ily but that does not look like u."
When the reality star posted another photo on Tuesday, people became even more certain that her features had been photoshopped.
The photo was another ad for her new KKW beauty range, and this time the brunette beauty wore a black bustier and choker.
Kim wrote in the caption:
"Matte Smoke! White eyeliner is one of my favorite looks with a 90’s inspo black smoke eye!
All of the lip liners for this collection are a few shades darker than the matte lipstick. I’m wearing lipliner & lipstick in 90’s Runway dropping 8.16 at 12pm pst Kkwbeauty.com"
Fans were bewildered by her appearance, with one commenting:
"Maybe I'm still drunk but wtf. How's that Kim?"
While fans are convinced the soon-to-be-lawyer looked heavily photoshopped, it's unlikely they will ever receive confirmation from the horse's mouth.
Last year, Kim shut down rumours she photoshopped a paparazzi picture of herself.
"I’m seeing online and on news media outlets that I suffered a ‘Photoshop fail.’ So ridiculous!" she wrote on her website and app.