Penelope Disick Sings With North West in Birthday Video
Credit: Kim Kardashian on Instagram    

North West

Penelope Disick Sings With North West in Birthday Video


Ready to feel old? Penelope Disick just turned four years old!

NEWS: North West & Penelope Disick Had the Best Mermaid Birthday Party

The only daughter out of Kourtney Kardashian and Scott Disick's three children celebrated her big day on July 8, and got a little help from her cousin North West, 3, who joined her in a song conducted in the pair's "secret language."

"Whatever secret language u girls speak, the way you girls protect each other & love each other is so special," Kim Kardashian, 35, captions a video of the performance on Instagram. 

PHOTOS: North West & Penelope Disick Raise the Cuteness Bar — Again

"Penelope, North is so lucky to have a best friend like you!" the proud aunt continues. "Happy Birthday my sweet P. I love you to the moon and back!"

Kourtney, 37, also took to social media to wish her daughter well on her special day. "Happy birthday to my little mermaid!" the reality star writes on Instagram. "Seeing the magic in the world through your eyes makes me so happy."

VIDEO: North West Talks to Kim Kardashian’s Fans in Adorable Snapchat

Happy birthday, Penelope! We look forward to the day when you're old enough to decode your secret language for us!