If you didn't know, TWICE is here to tell you that they're the ones who have stolen the hearts of ONCE.

In celebration of their 2nd debut anniversary, TWICE released a special video titled 'Who's the thief that stole the hearts of ONCE?'. Members of TWICE make an appearance one by one and admit they're the 'thief' behind the crime. 

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Check out the girls making the adorable confession in the clip.