AJ McLean to Cop -- Please Don't Bust Me ... I'm a Backstreet Boy!!!

Backstreet Boy AJ McLean came face-to-face with the long arm of the law early this morning ... and even though he didn't say it specifically, he TOTALLY tried to play the celebrity card to get out of a ticket.

McLean was pulled over in Hollywood around 1 AM when the LAPD noticed a problem with his license plates.

Once the boybander got out of the car, the plea for mercy was on ... with McLean explaining how he just wrapped up a concert tour ... and simply didn't realize there was a problem.

During the stop, McLean brings up the tour several times ... making sure the cop knew how big of a star he is.

Unfortunately, the officer seemed to be more of a New Kids on the Block fan ... and at one point, McLean says, "We actually just got off tour with them."

So how did it end? Turns out, McLean's registration was fine -- but the cop issued AJ a citation for not having the proper proof of insurance.