Media mogul Kris Jenner is mourning the loss of her younger sister, Karen Houghton.

The Kardashian-Jenner family matriarch, 68, posted a carousel of photos on Instagram featuring Houghton, who died at 65, with family members and snapshots from over the years.

"It is with the heaviest heart and deepest sadness that I share that my sister Karen passed away yesterday unexpectedly. My heart aches for my mom MJ and my niece Natalie (Zettel) and I pray that God guides us all through this difficult time. Karen was beautiful inside and out.

Jenner also wrote that Houghton was "the sweetest, kindest, the most sensitive and vulnerable and so so funny."

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"She always felt grateful and thankful for her life and treasured her family and friends and especially her beautiful daughter," Jenner continued in the caption. "She holds such a huge part of my heart and I cherish every single memory we have together. Karen’s passing is a reminder that life is so short and precious and tomorrow is never promised. We must tell those we cherish how much we love them. I love you my beautiful sister."

USA TODAY has reached out to reps for Kris Jenner for comment.

One photo included Jenner’s late ex-husband, lawyer Robert Kardashian Sr., and the sisters’ mother Mary Jo “MJ” Houghton, a frequent fixture on the family’s former show “Keeping Up with the Kardashians.” Another picture featured Jenner's sister and mom with her oldest daughter, Kourtney Kardashian Barker. One throwback included Houghton hugging her nephew, Robert "Rob" Kardashian Jr. alongside family pictures of the sister duo.

Houghton is survived by daughter Natalie Zettel and her fiancé, Noah, who popped the question in July 2022. On Mother's Day 2023, Zettel posted a photo of Houghton in a leopard print coat with a heartwarming caption.

"Happy Mother’s Day to all of the beautiful 😍 Mothers!!!! I love you momma ♥️I am always thankful for you. 🙏🏼" Zettel wrote.