More fans penned underneath the glamorous Instagram: "U PREGNANT?"; "Is it Kendall or Kylie that's pregnant?"; "Is she prego for sure like what"; "Are you pregnant?"; "Why does she look preg"; "She is pregnant..."; "Looks very pregnant to me."
MailOnline have contacted a representative for Kendall.
Ensuring all eyes remained well and truly on her physique, the raven-haired beauty scraped her tresses off her face into an up-do hairstyle.
Kendall wore deftly touches of make-up to highlight her youthful features in her mirror selfie.
She appeared to ignore the speculation mounting alongside her snapshot, with her fans' confusion coming shortly after Kendall's older sister Khloe finally confirmed she is expecting he first child with boyfriend Tristan Thompson.
To announce her exciting news, Khloe, 33, proudly debuted her naked baby bump ahead of the Christmas period, with both her hands and her boyfriend Tristan's hands caressing her growing stomach.
Addressing her 71,100,000 fans, she penned: "My greatest dream realized! We are having a baby...I still at times can't believe that our love created life!
"Tristan, thank you for loving me the way that you do! Thank you for treating me like a Queen! Thank you for making me feel beautiful at all stages! Tristan, most of all, Thank you for making me a MOMMY!!!" (sic)
Rumours first surfaced suggesting Khloe was expecting in October. They came around the same time sources claimed Kylie, 20, is set to welcome her first child with boyfriend Travis Scott.
She has been keeping a low-profile both on the showbiz circuit and on social media amid the claims and is yet to officially confirm her pregnancy.
Meanwhile, Kim, 37, is excited to welcome her third baby, a girl, via a surrogate with her husband Kayne West, 40.
The showbiz power couple, who married in May 2014, already have two adorable children daughter North, 4, and son Saint, 2.
