Scott Disick shares heartwarming photo with son Mason from inside private jet

Scott Disick has a built-in best friend for life in his firstborn son, Mason Disick.

The teenager is the first child the reality television star welcomed with ex-partner Kourtney Kardashian, who he dated for almost ten years, until 2015; they also share daughter Penelope, who just turned 12 , and son Reign, nine.

And despite Mason, 14, having been born into the spotlight, as he's grown up, he's shied away from appearing on any of his famous family's social media updates, though his dad did just make a sweet exception.

On Tuesday, Scott took to Instagram and shared a heartwarming post featuring Mason, a selfie in which he is fast asleep next to his dad while they travel on a private jet.

"Young blood knocked on the way home," Scott wrote in his caption, adding: "Best friend [four] life."

Fans were then quick to take to the comments section under the post to gush over the sweet moment, with one writing: "Crazy when Scott first had the kids he was so overwhelmed… now they are literally his saving grace," as others followed suit with: "Such a great father! These kids are being raised in such a great environment. Good for you Scott!!" and: "Looking good dad & son on a fancy plane! Hope you guys had fun!" as well as: "You are a great dad Scott!"

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Despite Mason's penchant for staying away from the public eye — much like his uncle Rob Kardashian — in recent years, he did recently leave both his family's fans and his own famous aunts speechless when he officially launched his first Instagram account.

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Back in May, Mason debuted his new Instagram profile , first sharing a photo of himself posing on a terrace with a forest view, wearing an Off-White black t-shirt and hiding his face with a cap. He made the post's song "Type [Expletive]" by Future.

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Though he had the comments section under the post largely disabled, his aunts Kim Kardashian and Khloé Kardashian were quick to express their disbelief over him joining the social media app, with Kim writing: "You're really on Instagram," with a tearful emoji, as Khloé added: "I can't believe this is happening."

MORE: Scott Disick reflects on emotional passing of time in personal message to beloved daughter Penelope

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The latter also gave her nephew a sweet shout-out by sharing his first post to her own Instagram Stories, and endearingly wrote: "I can't believe my @msondisick is on insta," noting: "The one who named us Kiki and KoKo is a legit teenager."

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At the time, he also shared two additional posts, one a carousel that first featured a photo with some of his friends, followed by two hanging out with his little sister Penelope in New York City, plus another carousel that featured a sweet mirror pic with his youngest sibling Reign.

Though he hasn't posted since June, he has shared two other posts featuring photos with his friends, all wearing baggy pants and Chrome Hearts gear. He is still only following his immediate family, his mom and dad, aunts Kim and Khloé, his uncle Rob, grandmother Kris Jenner , plus Kendall and Kylie Jenner.