5 Seconds of Summer's bassist is newly 19!

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Calum Hood turned 19 over the weekend on Sunday, Jan. 25.

He celebrated with his bandmates and on Twitter with his followers. 

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He eagerly tweeted, "EVERYONE CURRENTLY NEEDS TO HAVE A DRINK RIGHT NOW BECAUSE ITS MY BIRTHDAY NO EXCUSES," to kick off his birthday festivities.

He received plenty of birthday messages, including one from Capitol Records and 5SOS collaborator John Feldmann who called Hood "the beautiful smashing shredding bassist".

Hood's bandmates all wished him well too and celebrated him for a night out in Australia.

Luke Hemmings revealed Statement Clothing "hooked" them up with clothes so they'd look good for the celebration.

Michael Clifford said he forgot it was his bandmate's birthday at first, but then followed that up with a massive birthday wish.

Ashton Irwin Instagrammed a photo of Hood on stage, in which he shared in the caption, "Happiest of birthdays to you my man".

Hood shared photos from his birthday festivities on Instagram, including the one below.

Hood had letter balloons to spell out his name, but only captured the "A" and "L" in the following photo.

Other friends celebrated with Hood besides his bandmates!