Bella Hadid Wishes Sister Gigi a Happy Birthday: 'My Most Favorite Chilling Partner'

Bella Hadid celebrated her sister Gigi's birthday by sharing some adorable childhood pics of their family bond.

The supermodel, 26, penned a sweet birthday tribute for her sibling and fellow model, who turned 28 on Sunday.

Bella began her Instagram post with a cover photo of the sisters as flower girls in a wedding, writing, "Happy birthday to @gigihadid my best friend, my confidant, my teacher, my logic, my most favorite chilling partner."

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From there, shots alternated between more documentation of the duo when they were younger, plus some solo snaps of Gigi. The younger Hadid included photos of her sister as a child with a bloody cut on her face; with their mom, Yolanda Hadid; and a teenage moment petting a horse.

Adding an adorable photo of the two sleeping next to each other as kids, Bella continued in the caption, "Calm cool collected kind loving hard working angelic creative brilliant fun thoughtful PURE, the list of all of the reasons I love you could go on for days."

The carousel also featured a behind-the-scenes shots of the models holding hands, with Bella in a bright red dress and matching heels and Gigi in a silver metallic backless gown.

"I am always with you in spirit and your #1 cheerleader 365 days a year. I love you so much it hurts," Bella wrote.

Gigi commented on the post, "I LOVE YOU SO MUCH MY BELLOOONI🎈."

As seen on Gigi's own Instagram Stories, the mom of one celebrated her special day over the weekend at Walt Disney World, even posting a playful video of her lip-syncing to a cover of the iconic Little Mermaid song "Part of Your World" on her feed.

"Thanks for all the birthday love I've felt from here at Disney and all over the world," Hadid captioned Sunday's post. "💖 My heart is full of gratitude !!!! 🌞🧜‍♀️🏰💛."

The model also shared footage of fireworks shooting off at the park, and blowing out the candles on her birthday cake, which featured a childhood photo of her posing with Disney character Cinderella.