The reality TV star has been spotted hanging out with curvaceous model Blac Chyna on a number of occasions recently, including on a double date with their rap star boyfriends Kanye West and Tyga.
So it's no surprise that when Blac Chyna's tiny tot turned one-year-old over the weekend, Kim was there to celebrate with the family.
King Cairo was showered with love, affection and plenty of presents at a Disney themed party on Saturday (13 October), held at his rapper dad's LA mansion, and was treated to appearances from Goofy and Mickey and Minnie Mouse.
Mum-of-one Kim, 32, couldn't resist making friends with Minnie at the bash, as she posed for a photo alongside the famous cartoon character and Blac Chyna in a cute pair of mouse ears.
The sweet snap shows newly blonde Kim looking laid back in a plain white T-shirt, a pair of jeans and some knee-high brown boots.
She also appeared to have opted for a low-key make-up look, as opposed to the super flawless face she is usually seen with.
Meanwhile, Blac Chyna flaunted her tiny waist and killer hips in a cropped white top and some skinny jeans and she also donned the same pair of mouse ears as her new bestie.
Also at the start-studded party was Kim's sister Kourtney, who took along her one-year-old daughter Penelope Scotland.
Kourtney, 34, got in on the Disney fun too by taking a picture with Mickey and Minnie.
The two Kardashian sisters didn't arrive to King Cairo's celebrations empty handed either, as they gifted the littlun with a mini matte black Range Rover for him to ride around his house in.
Blac Chyna uploaded a video of herself and her son enjoying the extravagant present yesterday, along with the caption: "OMG I had to ....thanks from the Kardashian Fam!"
Apparently the urban model is set to appear by Kim's side in the new series of Keeping Up With The Kardashians.
Rumours have also been circulating that Kim is trying to help Blac Chyna land her own reality TV show.
What do you think of Kim's understated birthday party look? Let us know below, as the best comment each week wins £50!