Ong Seong Wu's birthday hashtag is trending worldwide.

On August 25 at midnight KST, fans of Ong Seong Wu took to Twitter with the hashtag '#ONG_HAPPY_DAY" ("#OngSeongWu_MomentOfBirthdayCelebration" in Korean) to celebrate the idol-actor's 25th birthday (in Korean age). Along with the hashtag, fans left countless messages and media footage of Ong Seong Wu from his early 'Produce 101' season and Wanna One years to his current days as an actor.

Check out some of the cute fan posts below, and happy birthday to Ong Seong Wu!