You may remember the video of Bieber fans becoming hysterical when they found out his September 30 gig was sold out.
It looks like the 17-year-old singer hasn't forgotten it, and now he's trying to locate a young female fan from the footage who seemed to take the disappointment very hard.
The Canadian star posted the video on his Twitter page and wrote: 'Need everyone's help. we have LESS than 24 hours. we need to find this girl.. she is at the 30 sec mark. HELP! thanks.'
Justin seems to have been moved by the girl's emotional reaction, and wants to make sure she makes it to his concert.