The 61-year-old reality star dedicated a sweet message to her only son on his birthday on Friday following his reported split from Blac Chyna.
"Happy birthday @robkardashian!!!! I love you more than words can say. You have the sweetest soul and the kindest heart, and I am blessed beyond measure to call you my son," Jenner captioned a collage of photos of Kardashian on Instagram.
"I am so proud of the man you have become and it brings me so much joy to watch you grow as a brother, son and father," she added.
"There are so many blessings in this life, but being your mom is one of the greatest. I love you!! #HappybirthdayRob."
Kardashian, who shares 4-month-old daughter Dream with Blac Chyna, split from the 28-year-old model in February following a highly publicized breakup in December.
Sources told People Jenner will support her son if he battles Blac Chyna for custody.
"Rob wants dual custody of their child and Blac Chyna is giving pushback," a source told the magazine.
"They are still figuring things out but she will certainly do whatever it takes to have Dream be with her for the majority of the time. Kris is backing Rob up 100 percent and won't let Chyna get away with anything that's less than fair," the insider said.
"The entire Kardashian family is there for Rob as well and supports him wholeheartedly. They are prepared to protect him in whatever way they need to do," the source added.
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