Justin Bieber at Nickelodeon Upfront Meet and Greet

Popstar! got up close and personal with Justin Bieber - he did a surprise performance at the Nickelodeon Upfront Presentation today in New York City! After he sang One Time and Baby, he took pictures with fans! Big Time Rush also wowed the crowd by singing their hit show's theme song! You'll see them and Victoria Justice and Miranda Cosgrove in this video too!