Khloe Kardashian and her entire family are ''exploding with joy'' over her sister Kourtney's new baby daughter.

The socialite has revealed the Kardashian clan - which includes her sister Kim and mother Kris Jenner - can't get enough of Penelope Scotland Disick since she was born on Sunday (08.07.12).

Khloe also insists Kourtney and her boyfriend Scott Disick's son Mason, two, has taken to his role as a Big Brother really well.

In a blog post, the 28-year-old star - who is married to basketball player Lamar Odom - wrote: ''I'm an auntie again!!! As I'm sure you all know, my beautiful big sister gave birth yesterday to the most perfect baby girl you've EVER seen - Penelope Scotland Disick!

''The entire family is literally exploding with joy and have not stopped fawning over our new little girl. And Mason is already loving being a big brother! This is just such a special and happy time for my family. Thank you to Kourt and Scott for making such beautiful babies! LOL. (sic)''

Khloe's older sister Kim, 31, also took to the internet to congratulate Kourtney, 33, and Scott on their new arrival.

The 'Keeping Up with the Kardashians' star wrote: ''Kourtney gave birth to a beautiful baby daughter on Sunday and the whole family is so thrilled to finally meet her! She is absolutely perfect! I am so excited to be an aunt again and can't wait to spoil little Penelope. I know Mason is going to be the best big brother in the whole world. Congratulations Kourtney and Scott. Xo (sic)''

Kourtney and Penelope have been ''resting'' comfortably since the birth.