Kourtney Kardashian's son Mason is unrecognizable in incredibly rare appearance on The Kardashians

Kourtney Kardashian 's oldest son, Mason, stunned fans when he stepped into the limelight on the most recent episode of The Kardashians .

Viewers were left doing a double-take when the 14-year-old was spotted at the end of the Season 5 finale inside his aunt, Kylie Jenner' s home.

She was hosting a dinner party for her famous family and the casual teen was embraced by his mom who could be heard saying: "My son."

But between his thick head of floppy hair and his statuesque frame, fans would be forgiven for not recognizing him.

It's the first time in years that the oldest child of Kourtney and her ex, Scott Disick, has been seen on screen.

© The Kardashians/Disney+

His appearance comes after his mom made an upsetting confession in the penultimate episode of the reality TV show about Mason spending time with her.

While she and her other kids, Penelope, 12, Reign, nine, and baby Rocky, joined her and her husband, Travis Barker, in Australia for a month, her oldest decided to stay home with his dad.

Kourtney admitted that made her sad but vowed: "I'm making the most of every second."

Speaking to her mom Kris Jenner, and sister, Kim, she said: "Mason isn't wanting to come [to Australia]. He's a teenager and wants to be with his friends and his dad." Sharing her upset, the 45-year-old added: "I don't want to not see him."

Kourtney spoke of the challenges of having four kids when she said: "I have kids all different age ranges — preteen, teenage, adults, infant — so I really do try to set aside one-on-one time with each of my kids.

"I don't want to miss anything. It's like a feeling of being pulled in different directions, wanting to be everything to everyone."

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As he's gotten older, Mason's relationship with his dad has only strengthened.

During a previous episode of The Kardashians , Scott caught up with Kris and Khloe and said of his relationship with Mason: "He's great, he's really been unbelievable," and endearingly noted: "We're closer than ever."

Mason is growing up fast and while he prefers a life away from the cameras, he has launched an Instagram account.

© Getty

He's amassed a following of 863k but rarely posts photos.

His first image sparked a reaction from his family with his mom commenting: "My first baby," Khloe writing: "I can't believe this is happening," and Kim adding: "You're really on Instagram."