The idol and former 'Produce 101' contestant took to Yue Hua Project's Instagram to celebrate the occasion with fans. He said, "The end of my adolescence! From here on, the adult Ahn Hyung Seob begins!! I met you all at the end of my adolescence, and I'm thankful to be able to bring it to a close happily~~~~. Please send more of your love in the future." 

Of course, netizens also discovered Ahn Hyung Seob's graduation yearbook photos and couldn't help but notice the idol's signature sass showing through. Check out the photos below!

[#형섭] 청소년 완전 끄읏 이제부턴 성인 안형섭 시작!! 청소년의 마지막에 여러분을 만났고, 가장 행복하게 마무리 할 수 있어서 감사했습니다~~~~~ 앞으로도 많이 사랑해주세요

A post shared by 형섭X의웅 (@yuehua_project) on Feb 2, 2018 at 4:33am PST