Oh boy. This is going to take up an entire month of Justin apologizing on "Ellen".

Last night, Ariana Grande's tour rolled through Los Angeles and featured a special surprise appearance from Justin Bieber. Things seemed to be going just fine during the performance until Bieber got a little too comfortable with Ariana and grabbed her around the waist during "As Long As You Love Me."

Ariana is in a pretty serious relationship with Big Sean so she quickly removed Bieber and went on with the show. People are reporting that Sean was at the concert and even sent out some angry tweets in Bieber's direction following the incident, but Sean is currently on tour in Canada. If this tweet (that was deleted) is real though, Biebs may consider watching his back. Or arming himself with eggs. Or both.

The incident can be seen at the 13:07 mark of the video above.