Kourtney Kardashian gave birth to a son – her third child with her longtime boyfriend Scott Disick – on Sunday, the birthday of her eldest son Mason.

Kourtney Kardashian Gives Birth

The birth of Kardashian and Disick’s second son was confirmed by People. The new baby, whose name has yet to be revealed, joins 5-year-old Mason Dash and 2-year-old Penelope Scotland.

“The family is freaking out with joy,” a source told E! News. “What an amazing coincidence.”

Check Out Kourtney Kardashian’s uBio HERE

Despite the excitement of welcoming a new baby into the family, Kardashian made sure to recognize Mason’s fifth birthday on Instagram, captioning a photo of him, “Happy birthday to the coolest little boy in the entire world.”

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

News broke back in June that Kardashian and Disick were expecting for a third time. The pregnancy was eventually confirmed on an episode of Khloe and Kourtney Take the Hamptons in which Kardashian told Disick that another baby was on the way. It was revealed that their third child would be a boy on last week’s episode of the reality TV series.