Gigi and Yolanda Hadid Wish Bella a Happy Birthday With Adorable Throwback Pics

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Happy 20th, Bella -- your family clearly loves ya!

Gigi Hadid wished her younger sister, Bella, a happy birthday in the cutest way possible.

The 21-year-old model posted a precocious throwback snap to Instagram on Sunday. Little Gigi and Bella appear to be doing stretches in copycat poses while out on a balcony.

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The photo was accompanied by a sweet message from Gigi reading, "Happy Birthday to my baby sister @bellahadid ?? Your beauty and beautiful heart blow me away more every day. You make me more proud than you'll ever know, and I feel so grateful that we get to experience so much by each other's side. ? Can't believe you're 20!!!!!!!!!!!!!!!!!!! Love ya miss ya kiss ya ?."

The ladies' mom, Yolanda Hadid, shared an equally adorable kid pic of the birthday girl, as well as her own lovely note.

"Happy Birthday my sweet Angel..... I pray that each day, love, health and happiness will come your way," the 52-year-old mom of three wrote on Instagram. "Thank you for being YOU, I am so proud of all that you do and all that you are. You are my everything! #ILoveYou #MyBirthdayGirl."

PHOTOS: Gigi and Bella Hadid Go Full Model for Night Out Together

As for Bella, she also went the throwback route, posting a black-and-white photo of Yolanda cuddling her then-newborn. "20 years ago with the woman who birthed me," the model wrote on Instagram along with a prayer hands emoji. "I love you #20."

Of course, the social media posts wouldn't be complete without a goofy moment. Bella also shared a meme of a person high-fiving themselves that she captioned, "This is 20."

The fashionista appeared a bit wistful about leaving her teen years behind, however. Just hours before turning 20, she tweeted, "I wanna be 18 again."

Don't worry, Bella -- your twenties are looking good already!

WATCH: Bella Hadid Rocks Tiniest Tube Top Ever, Gets Major Praise From Coco Rocha For Modeling Skills

The in-demand model has been very busy lately, walking runways at New York Fashion Week and Milan Fashion Week, partying with Gigi and other famous faces in Europe, and even making her way to Tokyo to with her boyfriend, The Weeknd. 

Not only that, but she's done quite a few sultry photoshoots as of late, including a spread for Flare magazine that featured a wet T-shirt and topless pose. Find out more in the video below.