Kim Kardashian's Birthday IG Tribute To Kourtney Is Filled With The Best Throwback Pics

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In case you haven't heard, April 18 marks Kourtney Kardashian's 40th birthday. Naturally, the b-day girl's famous family is pulling out all of the stops on social media to celebrate. And Kim Kardashian's birthday message for Kourtney Kardashian contained throwback photos that are almost too adorable to handle.

Kim celebrated her sister's birthday by posting a gallery of photos on Instagram that featured some of their cutest and most special throwback moments. The KKW Beauty mogul posted numerous snaps of herself and her older sister when they were tots, including a couple of the sisters posing with their late father, Robert Kardashian Sr. They could also be seen in the pics showing off their Care Bears, posing in matching yellow outfits, and, as teens, in chic ensembles with one of their friends.

Based on the photos, one can gather that Kim and Kourtney were super close when they were kids, just as they are today. In addition to sharing some adorable throwback pics, she also wrote a beautiful message for her sister, highlighting just how much the birthday girl has taught her over the years. Kim wrote:

"Happy Birthday @kourtneykardash I honestly can’t believe the life we have lived! It’s such a dream to go through it all with having a sister like you by our side! You have taught me so much throughout life. You’re such an amazing mom and friend! Can’t wait to celebrate you tonight! I love you beyond what you could imagine ✨"

As previously mentioned, Kim and Kourtney have such a close bond and have experienced a ton of milestone moments together. Many of those moments have, luckily, been featured on Keeping Up With the Kardashians. In a bonus clip from the series, Kim pulled out all of the meaningful stops for her elder sister's birthday during the crew's Iceland vacation back in April 2016.

For Kourtney's 37th birthday, Kim got her sister a Snoopy snow cone machine, explaining, "All we wanted to was go to MJ's house and my grandma worked and my grandpa didn't. So, my grandpa would sit home with us and make those with us all day long. All we wanted was a Snoopy snow cone." How special is that? Later in the clip, Kim presented her sister with a vegan-free, dairy-free cake, which was just too perfect.

Of course, Kim wasn't the only one who took to social media recently to celebrate Kourtney's 40th birthday. Kris Jenner and Khloé Kardashian both posted some sweet birthday tributes to the Poosh founder. Khloé posted her own Kourtney-focused photo gallery and a message about the pair's "incredible rare bond," writing:

"You and I have an incredible rare bond that no matter what, it can never be broken. You’re my best friend, one of the rare few I can count on most in my life. I’m so thankful for that. I know that so many people go through life without their sister as their best friend, or without a sister in general and I don’t know how they do it. Honestly, without you my life would be boring and not as full."

If you somehow didn't know it already, all of these birthday tributes are sure to showcase just how close the Kardashian family is.

Whether she's gifting her sister with a nostalgic present or posting a throwback-themed tribute on Instagram, Kim definitely knows how to celebrate Kourtney's birthday in some truly meaningful ways. Same with Khloé.