Kourtney, 35, and her long term partner Scott Disick, 31, welcomed the baby boy on Sunday, according to a report on Us Weekly.
The couple have yet to formally announce the birth.
The baby is the third child for the pair, who are also parents to Mason, five and Penelope, two. (Coincedentally, it was also Kourtney’s eldest son Mason Disick’s fifth birthday yesterday, so the siblings will share a birthday.)
There is no word yet as to whether notorious momager Kris Jenner will be taking the baby boy on as a client.
Kourtney and Scott have been together since 2006, although they have had a rather tumultuous relationship.
Kourtney and Scott.
Disick, who recently lost both of his parents within three months of each other, initially struggled with the news that he would be a father for the third time.