WDW Wishes Zach Herron a HBD on Instagram

They grow up so fast!

In case you missed it, Why Don’t We‘s youngest member Zach Herron is officially 18! And to help him ring in another year around the sun, the rest of WDW — aka Jonah Marais, Daniel Seavey, Corbyn Besson, and Jack Avery — and some of the singer’s closest friends and family members took to Instagram this weekend with heartfelt messages and oh-so-sweet pics. Too cute!

From his younger siblings Reese and Ryan to his bandmates and everyone in between, we’ve rounded up a handful of the HBD posts to celebrate. Keep scrolling to check ’em all out!

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HBD, #ZachHerron 🥳🎉✨Join us in wishing this #WhyDontWe cutie the best birthday ever & fill the comments with hearts! ❤️❤️❤️

A post shared by TigerBeat (@tigerbeatnow) on May 27, 2019 at 12:33pm PDT

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happy 18 bro love u

A post shared by Why Don’t We (@whydontwemusic) on May 26, 2019 at 5:53pm PDT

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happy birthday @imzachherron, you won’t be lying when you tell people you’re 18 anymore 😂 no but straight up we’ve been around the world together and you’re my little brother and i’ll always look out for you. let’s celebrate 🎉♥️

A post shared by Jonah • WHY DON’T WE (@jonahmarais) on May 27, 2019 at 2:03am PDT

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can’t believe it’s your earth day. Happy 18 lil bro ✊🏼⚡️

A post shared by Jack Avery • WHY DON’T WE (@jackaverymusic) on May 27, 2019 at 7:16am PDT

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Happy birthday @imzachherron. 18 already looks good on u 😂 love u bro

A post shared by Daniel • WHY DON’T WE (@seaveydaniel) on May 27, 2019 at 7:20am PDT

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Happy 18th Birthday brother. we’ve talked about this day for so long and you finally made it. who woulda thought you’d celebrate in Tokyo, Japan tho?? you’re too fly. love you bro

A post shared by Corbyn • WHY DON’T WE (@corbynbesson) on May 27, 2019 at 7:14am PDT

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What to say about Young Herron. Well he ain’t so young no mo! Met this kid when he was 15 and we’ve been brothers ever since. Happy birthday bro, so proud of the man you are becoming. 18 looks good on you🙌🏼💯 love you my guy

A post shared by EBEN (@ebenofficial) on May 26, 2019 at 8:26am PDT

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Happy official birthday to this one! My sweet goofball. ❤️ #howareyou18already . . . (posted at exact time he was born 18 years ago – 12:14 CT)

A post shared by Myta Herron (@mama.herron) on May 27, 2019 at 10:14am PDT

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Turning 18 is a strange thing…with the passing of a single day you are considered an adult. As a parent, it is a day to reflect on the moments that have lead up to this milestone. A day to hope that each teachable moment has established a solid foundation for you to thrive in adulthood. Being your dad has been one of my greatest accomplishments. Eighteen years ago today I had no idea what it meant to be a father and to love unconditionally. In a single instance it was no longer just about me, but about providing a healthy, secure, and happy environment for you to be who you were meant to be. Watching you grow into the man you are today has been an honor and I look forward to being a part of this next chapter of your life. Wishing you the happiest of birthdays. Love you Big Time!!! @imzachherron

A post shared by Josh Herron (@joshherr0n) on May 27, 2019 at 12:41am PDT

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happy birthday big bro, thanks for always being there for me , and being such a big inspiration to me . much love bro hope 18 treats you well ❤️ ( peep scooby doo and the crocs 😎)

A post shared by ryan herron ツ (@imryanherron) on May 27, 2019 at 12:26am PDT

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It’s now your birthday in both time zones!!! 🤗 Happy birthday Zachy! I just want to say that I love you so so so much!!! You make me laugh and you take care of me!!! And I love every second you’re home! I’m super proud of you and I love all the music you make! I hope you have the best day ever! I can’t wait to squeeze you and give you the biggest hug! 💕 @imzachherron

A post shared by Reese Herron (@imreeseherron) on May 27, 2019 at 12:12am PDT

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Happy Birthday.. Again.. cuz I posted to soon.. cuz we’re in Japan.. and time zones.. and.. ya.. k bye.. love you bro 🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗

A post shared by Zack Caspary (@zcaspary) on May 27, 2019 at 9:16am PDT