Justin Bieber finally released "What Do You Mean?" after an epic, month-long countdown, and a bunch of your favorite celebrities helped him debut his video. Everyone from Ariana Grande to Little Mix to Austin Mahone helped the pop star work that promo, and it's kind of amazing!
He had so many stars posting their own "What Do You Mean?" photos and videos that it was pretty hard to keep track of everyone. So in honor of his latest single, we've rounded up the highlights from Justin's countdown. Can you believe it's already been 30 days?!
Click through to see all the celebs you totally forgot took part in his project, and let us know if there's anyone you think he should have included in the comments!