Even if you've been keeping up, this pic might still catch you by surprise.
After all, Kim Kardashian recently shared family photos, and featured in the carousel was Kourtney Kardashian and Scott Disick's 13-year-old son Mason Disick, marking a rare sighting for the teenager.
In the photos, Mason holds up a peace sign while his dad drapes an arm around him. Also posing with the pair? Mason's sister Penelope Disick, 11, as well as cousins North West, 10, Saint West, 8, Chicago West, 5, and Psalm West, 4.
Kim simply captioned the Dec. 11 post, "Everything."
And her followers agreed, with many stunned at how grown up Mason looked. "Shut UP. why does mason look 17," commented one user, while another added, "Omg WE HAVENT SEEN MASON IN FOREVERRRRRRRRRRR!!!!! Our little internet nephew GREW UP!!!!!!!!!!!!"
But while he might be the internet's nephew, Mason also plays an important role in his IRL family: big brother. A role that became that much more important when Kourtney gave birth to her and Travis Barker's first child, Rocky Thirteen, in November.
Indeed, baby Rocky joined a large, blended family. In addition to counting Penelope as his sibling, Mason also is big brother to Reign Disick, 8. Plus, Travis is dad to Landon Barker, 20, Alabama Barker, 17 (with ex-wife Shanna Moakler) and stepdad to Atiana De La Hoya, 24.
It's a concept that has always appealed to the Poosh Founder, who tied the knot with the Blink-182 drummer in 2022.
"I love the idea of a blended family," Kourtney said during a confessional on season two of The Kardashians. "I think the more kids the merrier. You have all these siblings and more people to love, and it's a beautiful thing."
Keep reading for more of the Kardashian-Barker family's best moments.
Celebrating Dad
Kourtney Kardashian and husband Travis Barker were joined by his son Landon Barker—who he and ex Shanna Moakler share alongside daughter Alabama Barker and Atiana De La Hoya, her daughter with Oscar De La Hoya—at GQ's Men of the Year party in November 2022.
Mom & Me Mirror Selfie
Penelope Disick—who Kourtney and ex Scott Disick share alongside sons Mason Disick and Reign Disick—appeared with her mother in a 2024 vacation selfie from Australia.
Australian Summer
Reign and Penelope enjoyed some fun in the sun during their 2024 family trip to Australia for Blink-182's tour.
Kravis Down Under
Kourtney and Travis stopped for photo ops while in Australia.
Boys Club
In honor of Landon's 20th birthday in October 2023, Kourtney shared a throwback photo from six years earlier of the then-teenager hanging out with Mason.
Girl Gang
Alabama snapped a silly selfie with Atiana, Kourtney and Penelope, during The Kardashians star's May 2022 wedding with Travis.
Here Comes the Bride
Kourtney took a break from her wedding festivities in to pose for a selfie with Alabama.
Meet the Kardashian-Barkers
All in the family: Alabama, Reign, Travis and London joined Kourtney at the April 2022 premiere of The Kardashians.
Front Row
Kourtney's oldest son Mason, Alabama and Atiana tagged along for Travis and Kourtney's front row outing at the AMIRI fashion show in February 2022.
Alabama and Penelope
'Tis the season to share sweet throwbacks. Kourtney celebrated Alabama's Christmas Eve birthday in 2022 with an older snap of the birthday girl and Penelope.
Birthday Bunch
Kourtney, Travis, Alabama, Atiana, Landon and Reign posed at Disneyland for Kourtney's birthday outing in April 2022.
Magic Kingdom
Why, yes, it was the happiest place on earth to mark Kourtney's 43rd birthday.
The Three Mouseketeers
Landon, Atiana and Kourtney found the magic for this fun snapshot.
A Fashionable Family
Kourtney and Travis took Alabama to Tommy Factory's New York Fashion Week show in September 2022.
A Portrait by Penelope
Penelope the artist! Travis shared her drawing of him in a March 2022 post.
Family Portraits
On Christmas Eve 2021, a newly engaged Kourtney (with Penelope) got merry with her soon-to-be husband and his crew.
Fun and Games
Travis and Penelope enjoyed a game of checkers, while Kourtney and matriarch MJ Houghton observed the action.
The Sweetest Age of All
For Alabama's 16th birthday in December 2021, Kourtney and Travis surprised her with balloons that spelled out "BAMA 16."
Sharing the moment, Travis captioned the post, "I LOVE YOU SO MUCH!!!"
TikTok Fun
Travis appeared with Kourtney and Penelope in a 2021 TikTok video posted to the mother-daughter pair's joint account.
Welcome to the Fam
"So happy for you guys," Travis' daughter Alabama wrote on a photo celebrating the couple's October 2021 engagement. "I love u both!"
Amusement Park Fun
Landon joined his dad and Kourtney for some Halloween 2021 fun at Knott's Scary Farm in Southern California.
All the Halloween Activities
Kourtney recruited her son Mason for a trip to Universal Studios' Halloween Horror Nights with Travis and his daughter Alabama in 2022.
Frankenstein Friends
Atiana posed as the Bride of Frankenstein to Reign's Frankenstein's monster during the spooky outing.
Costume Cutie
Penelope horned in on the fun in a devil costume as the crew headed to the Los Angeles immersive jack-o-lantern experience Nights of the Jack in 2021.
A Memorable Moment
During their Nights of the Jack adventure, Alabama captured Travis and Penelope sharing a sweet moment as he walked around carrying her on his shoulders.
The Ultimate Throwback
Even before they were dating, Travis and Kourtney were friends for years. Just look at this throwback photo of Mason, Landon, Alabama and Penelope from 2017.
Rockstar Training
Dare we say this birthday present rocks? Travis gifted Penelope a state-of-the-art drum set for her ninth birthday in July 2021.
Family Photo
The couple made their own fireworks when they celebrated the Fourth of July at Disneyland with Landon, Alabama and Reign in 2021.
Twinning
Atiana and Kourtney plowed ahead in matching snow gear during their first family trip to Utah's Deer Valley in April 2021.
Snow Day
Who needs to hit the slopes when you've got snowmobiles? Alabama joined in on the fun with Kourtney and Atiana.