Kim Kardashian left fans stunned when she shared a photo of her nephew Mason Disick in honor of his 13th birthday on Wednesday.
The mom-of-four took to her Instagram Stories to wish her sister Kourtney Kardashian's eldest son a happy birthday, but fans were distracted by how grown up the teenager looks and how he towers over his petite aunt.
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In the image, Kim and Mason are standing back-to-back, and it's clear to see that he is already taller than Kim's 5'2 frame.
"The day has come where you're taller [than] me now," she wrote across the photo. "I just love who you are and I'm just so proud of you Mason. Welcome to your teenage years. Happy Birthday."
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The photo was reshared by a Kardashian fan account on Instagram, and fans of The Kardashians star were quick to comment on Mason's appearance.
"Omg?? I was so confused who that was at first. Mason has grown up so fast!!! Didn't even recognize him," replied one. A second said: "Mason looks so grown up!" A third added: "Happy birthday mason from Australia you have grown so much."
Fans were in disbelief over Mason's 'grown-up' appearance
It wasn't just Mason who was celebrating a birthday. His younger brother Reign was also born on 13 December, but five years after his sibling.
Taking to Instagram to share a throwback photo of Mason and a baby Reign, who is now eight, proud mom Kourtney wrote: "December 14th… one of the best days of my life, twice and forever. My birthday boys."
Kourtney also shares her daughter, Penelope, ten, with her ex-partner Scott Disick.
Mason shares a birthday with his younger brother Reign
Mason and Reign's grandma, Kris Jenner – who the children call Lovey – also paid tribute to her grandsons on their special day alongside several throwback photos. "Happy birthday to two of the brightest lights in my life, my beautiful grandsons, Mason and Reign!" she wrote.
"Both of you have the most amazing qualities and are kind, considerate, loving, so smart, so talented in so many ways, and such a special magical part of our family… AND it's wild that you were born on the very same day!!!! Five years apart!!!!"
Kris concluded: "You are both the best sons, grandsons, brothers, nephews, and friends to all of us and I love you so much!!!!!!! Lovey xoxo."
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