The rarely-seen young boy looked incredibly grown up, with a full head of curly hair and big brown eyesCredit: Instagram

Tatum was born via surrogate with on-again, off-again boyfriend Tristan Thompson, 32, one year ago.

After mainly posting photos of him as a newborn, Tatum looked incredibly grown up in the pics posted by Khloe, 39.

For the first pic, the Good American founder chose a shot of her holding Tatum on her hip, with the young boy sporting a full head of curly hair and looking tall as his legs dangled long past his mom’s torso.

The second showed Tatum sitting on a marble step as he trained his big brown eyes on the person behind the camera.

The young boy wore a woven fedora on his head, and also sported blue Dior swim shorts worth $270.

Another shot showed him playing with his big sister, True Thompson, five, in the bath, while others showed the boy in costume for various Kardashian parties.

One throwback photo displayed Tatum as a tiny newborn, surrounded by his sister and two of his young cousins; North West and Penelope Disick.

SWEET MESSAGE

Along with her selection of photos, Khloe added a touching caption to the social media post in honor of her youngest child.

In one paragraph of the long message, she wrote: “I am a firm believer in that God gives you what you need and I needed you. God knew my heart needed you.

“I needed your sweet and precious Smile. I needed your angelic spirit. I needed a love only you could give me. I needed my son.”

Another tract from the mother of two read: “Tatum, You have changed mine and True’s lives forever. We both needed you. I knew she would be a fantastic, loving older sister, but I don’t think I ever could’ve imagined the love and bond you guys already have.”

She also referenced her younger brother, Rob Kardashian, 36, and wrote: “You both remind me so much of uncle Bob and I.

“It’s fitting since I think you look soooo much like your uncle. (Which means I think you look like my dad too).

“I cannot believe you are already one happy first birthday my sweet sweet baby.”

FAMILY WOES

Alongside Tatum, Khloe and Tristan share a daughter; True.

Tristan also has a six-year-old son named Prince, but the basketball star has yet to meet his other one-year-old son, Theo, who was conceived with Maralee Nichols when he was still in a relationship with Khloe.

Maralee’s name first grabbed the media’s attention around her son’s birth, when it was revealed that Tristan had an affair with the fitness model.

Tristan issued a public apology to Khloe after paternity results confirmed he was the father.

Fans speculated that the TV personality had welcomed her ex back into her life after the unexpected death of his mother.

Most recently, Khloe revealed that Tristan and his younger brother, Amari, 16, were living with her after the roof of Tristan’s Los Angeles home caved in due to flooding.

In her touching message for Tatum, Khloe talked about the ‘love and bond’ shared between him and his older sister, True ThompsonCredit: Instagram

The Hulu star said that the children’s bond reminded her of her own with her younger brother Rob Kardashian, and also said that Tatum resembled his uncleCredit: Instagram/robkardashianofficial

Khloe shares Tatum and True with Tristan Thompson, from whom she initially split after news of his fathering of another son while they were expecting Tatum became publicCredit: Hulu