Tommaso Boddi/WireImage
Lara Walsh
Jan 16, 2017 @ 3:00 pm

It looks like Pink's 5-year-old daughter Willow is completely smitten with her younger brother.

The Hart family welcomed their newest addition, Jameson Moon, in late December, and big sis Willow couldn't have looked happier ringing in the new year cradling the sleeping infant in her arms.

Now the pink-maned toddler is officially celebrating her initiation into the big sisters club with an adorable "big sister party" complete with chocolate cake, balloons—and her little brother, of course!

Pink took to Instagram to document the celebration on Saturday, sharing an adorable photo that shows her oldest child holding a chocolate cake decorated with a pink bird and the words "Congrats big sis!" while mom holds a swaddled sleeping baby Jameson. Green and pink balloons decorate the background.

Instagram/pink

"Congrats Big Sis! #bigsisterparty," the 37-year-old proud mom captioned the sweet shot.

RELATED: Pink's Daughter Rocks Pink Hair as She Holds Her Baby Brother

Could this family get any cuter?

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