When Seth Rogen called Justin Bieber "obnoxious" and "ungrateful," in addition to many choice words, but the young singer was not going to take it. Bieber took to Twitter to put the funny man on blast.

"Seth Rogan (sic) sorry I didnt bow down when I asked 2 meet u was probably a bit shy and didn't want to be over the top but still. love ur movies."

The "Neighbors" star told Howard Stern the Biebs asked to meet him during a European TV show appearance.