Ahead of Bella Hadid's 21st birthday today, older sister Gigi Hadid shared the most adorable throwback picture of the pair from day the famous duo first met.

Last night, the blonde-haired supermodel posted a picture of herself hugging new born Bella to Instagram.

She captioned the snap: TOMORROW WILL BE 21 YEARS SINCE I MET MY FOREVER BESTIE @bellahadid ❤️ (me wearing all red on your actual day of birth is MAJOR and possibly the reason it's your favorite color 😜).

instagramView full post on Instagram

The 23-year-old Californian beauty also took to Instagram Stories to share a picture of a drawing she'd done in 2011 to celebrate her sister's fifth birthday, which Bella later shared on social media and revealed the snap even made her cry.

Bella HAdid | ELLE UKpinterest
bellahadid//Instagram

Over the weekend, the face of Dior Beauty landed back in New York City ahead of her birthday celebrations, which already appear to be well underway.

Bella HAdid | ELLE UKpinterest
bellahadid//Instagram

Last night, Bella shared numerous videos of her chilling with her best friends who were in the process of hanging up balloons and birthday decorations around the supermodels' flat for the milestone occasion.

Bella HAdid | ELLE UKpinterest
bellahadid//Instagram

Happy birthday Bella!