"18 YEARS AGO MY LIFE WAS BLESSED W THE MOST SPECIAL AND AMAZING LITTLE BROTHER ON DA PLANET," Gigi captioned a cool black-and-white snap of herself and her baby bro. "@anwarhadid you amaze me more every year- watching you grow and thrive in exactly who you are makes me more proud than you'll ever know. You inspire me and so many around you, and I feel so lucky to be your blood! HAPPY BIRTHDAY love you foreva ??✨???."
Bella also shared a couple of childhood photos alongside a sweet message praising her little brother.
"Happy birthday my sweet angel. Your love and light is worth all of the stars in the sky! I'm so proud of the man you have become and are becoming. I'm so proud and lucky to call you my brother," she wrote. "Nobody loves you more than me my mini me ? @anwarhadid ????forever and ever and ever x infinity .. 18 years you're still my best friend and favorite man !"
"❤️Happy 18th Birthday my sweet angel, thank you for all the light you bring into my life, you inspire me to be the higher me," Anwar's mom, Yolanda Hadid, shared alongside a baby photo. "Your kindness and consciousness is the greatest gift I treasure everyday so thank you for all that you do and all that you are to me and your sisters...... #loveYou #AlwaysAndForever #June22."