Seth Rogen Comes Face to Face With Justin Bieber After Their "Beef"

Seth Rogen stopped by The Ellen DeGeneres Show on Wednesday and opened up about his infamous "beef" with Justin Bieber. Seth, who tweeted that the singer was a "piece of sh*t" back in January 2014, admitted to Ellen that he doesn't really know why he started the fight in the first place. "I just called him some really mean things on social media for no real reason," Seth explained. "And I only met him very briefly. It was really just something I can't tell you why I did it. I was inclined to do it in that moment, and then I did it. And then it really hurt his feelings." Seth, who also talked about working with Zac Efron in Neighbors 2, then revealed that the two made up after running into each other backstage. Watch the funny clip above, and then check out Justin opening up to Ellen about Selena Gomez.