By Meghan Overdeep
Oct 31, 2016 @ 10:15 am
Bruce Glikas/WireImage

They grow up so fast! Neil Patrick Harris reminded us of this bittersweet fact on Sunday by documenting the loss of his 6-year-old daughter's first tooth on Instagram. In the smiling 'gram, Harper—who is one half of Harris and husband David Burtka's impossibly cute set of twins—displays her fallen tooth proudly while flaunting the new gap in her pearly whites.

"Very exciting—Harper lost her first tooth!" Harris, 43, captioned the sweet snap.

"AND she woke up to find that the Tooth Fairy had left a Lin-Manuel Miranda under her pillow! #rich," he added.

The last few months have held a lot of excitement for Harris, Burtka, Harper, and her twin brother, Gideon. In addition to starting kindergarten and celebrating their sixth birthday, the couple recently took their little ones on an envy-inducing family vacation to the Dominican Republic. And we can only imagine the anticipation they're feeling leading up to their epic annual family Halloween costumes later today.

RELATED: Neil Patrick Harris's Stylish Twins Are Too Cute—See Gideon and Harper Burtka-Harris's Sweetest Moments

We know we're counting down the seconds until the great reveal!

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