Kourtney Kardashian gives birth to a baby boy!

Cape Town – Kourtney Kardashian and Scott Disick have welcomed their new baby boy into the world!

Baby number 3 was born on Sunday, which is also Kourtney’s eldest son , Mason’s fifth birthday E! News has confirmed.

Kourtney posted a birthday picture of Mason before the birth of his new baby brother.

Happy birthday to the coolest little boy in the entire world. You teach me so much every single day and changed my universe the second I met you. You have taught me what life is all about and I am truly blessed and honored to be your mommy.

A photo posted by Kourtney Kardashian (@kourtneykardash) on Dec 12, 2014 at 12:25pm PST

The rest of the Kardashian clan also took to social media to wish the celebutot a happy birthday before they welcomed their new family member.

he's 5 and I can't take it! stop growing so fast buddy! love you Mase ??

Ein von Kendall Jenner (@kendalljenner) gepostetes Foto am Dez 12, 2014 at 5:59 PST

Stop growing up! How are you 5 already?!?! My ace! My Mase!

A photo posted by Khloé (@khloekardashian) on Dec 12, 2014 at 5:37am PST

Happy Birthday to the lego master Mason!!! You are so big I can't take it! You are my everything! I love you so much! pic.twitter.com/eGU0ffP7ZO

— Kim Kardashian West (@KimKardashian) December 14, 2014

Happy Birthday my precious little Mason!!!! You have brought so much love and joy into our lives and I can hardly believe you are 5 today!!! I love you so much....#blessed #family

A photo posted by @krisjenner on Dec 12, 2014 at 7:58am PST