Kylie Jenner Fans Shocked After Seeing How Tall Stormi, 6, Is in TikTok With Her Brother Aire, 2: 'She Grew Up So Fast'

Kylie Jenner 's kiddos need to slow down, because they are growing up way too fast!

On Thursday, October 10, the reality star hopped on a recent TikTok trend with both her daughter, Stormi , 6, and son, Aire , 2 — and fans couldn't believe how big Jenner's children had become.

In one of the videos Jenner shared to TikTok on Thursday, the Kylie Cosmetics founder, 27, could be seen flipping Stormi around in the air alongside audio from Jack Johnson 's hit song, "Upside Down."

"I wanna turn the whole thing upside down," the lyrics said, as Jenner turned Stormi in a full flip while the 6-year-old giggled adorably in a pair of long-sleeved pajamas and two pigtail braids.

Jenner, for her part, was dressed casually in black lounge pants and a white tank top.

In the comments section of the post, fans couldn't believe how much older Stormi looked since they last tuned into one of Jenner's social media channels .

"OMG THIS IS STORMI? she grew up so fast.😭💗💗," one admirer gushed, as another noted: "She's getting soo tall 💗."

"She’s going to be a model like her aunty!! She is so tall🥹," a third supporter declared in reference to Kylie's sister, Kendall Jenner , 27, while a fourth fan exclaimed: "OMG LOOK HOW TALLER [sic] SHE IS 😭. SHE'S GROWING SO FAST😭🩷. LOVE HER, SHE'S SO CUTEEE 🫶🏻🥹."

Of course, Kylie couldn't do the TikTok trend with just one of her and ex Travis Scott 's two children, as Aire wanted to participate, too!

In a clip shared right around the same time as the video with Stormi , Kylie stood with her precious toddler — who also wore a pair of pajamas — before flipping the tiny tot around with the same "Upside Down" song playing in the background.

In the second upload, Stormi lip-synced the lyrics off to the side before the trio broke out in laughter.

After seeing rare footage of Aire, fans jaws were to the floor, as many noticed how much the little boy has started to look like his mom.

"Stoppp Aire looks just like youu 🥹," one TikTok user noted, while another added: "Wait he’s so grown up 😩❤️."

"He's your twin 🥹🥹🤍," a third fan declared, as a fourth gushed: "AWWWW THEY'RE SO CUTE. YOU'RE SUCH A CUTE LIL FAMILY."

Kylie and Travis welcomed Stormi in February 2018 but split briefly before rekindling their relationship in 2021.

The exes went on to have their son, Aire, in February 2022 — though they called it quits on their on-again, off-again romance by the end of that same year.

In January 2023, a trustworthy source confirmed Kylie and Travis, 33, were officially broken up, and it wasn't long before the makeup mogul moved on with her new boyfriend, Timothée Chalamet , 28.

Kylie and the Wonka actor hard-launched their relationship in September 2023, when they packed on the PDA at Beyoncé 's concert and at the U.S. Open in New York City.