Justin Bieber and Chris Brown surprised the crowd at Acer Arena in Sydney on Thursday.
Bieber, who got his start by posting videos of songs by Chris Brown and Justin Timberlake on youtube, brought out Brown on stage to perform "Look At Me Now."
Justin uploaded the performance to his youtube and wrote, "3 years ago I sang WITH YOU by Chris Brown in my living room. Since then thanks to the help of the fans we have been on an incredible journey. Thank you because we are just getting started. NEVER SAY NEVER. "
(Photo: Getty Images)