It's hard to believe Dec. 3 marks three years since Michael Clifford, Calum Hood, Ashton Irwin and Luke Hemmings became 5 Seconds of Summer.

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The band made an event for the special occasion on Facebook.

Clifford, Hood, Irwin and Hemmings said, "The band turns three years old on December 3 !! It's been an incredible last three years, and we're so lucky to be doing what we do thanks to you guys."

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The Aussies also shared a link to a playlist on their YouTube Channel that they made of videos of themselves over the course of the last three years. The playlist is so appropriately called #5SOS3RDBDAY. It contains 32 videos in all. The last video is of their What I Like About You American Music Awards performance while the first video on the playlist is of a very young looking Hemmings from 2011 covering Please Don't Go by Mike Posner.

The band's drummer Irwin even took to Twitter to share how blown away he is by the band turning three and all they've accomplished thus far since he said, "never in my wildest dreams would I of guessed any of this could of happened." See his full tweet below.

He even shared "an embarrassing early cover" they did "to celebrate" their third birthday. It's an All Time Low song, which is included on their birthday celebration playlist.

Happy birthday, 5SOS! Here's to many more!

Tags: 5 seconds of summer