On the 10th, Justin Bieber's first Korean concert as part of his 'Believe Tour' opened at the Olympic Park's gymnasium in Seoul.  After performing his hit songs for about fifty minutes, he said he would introduce a guest.  At that time, G-Dragon made a sudden surprise appearance to perform his song "Crayon."

SEE ALSO: Justin Bieber enjoys a meal at the YG cafeteria

G-Dragon was welcomed warmly by the crowd as all of his Korean fans got on their feet. The response to G-Dragon seemed even more enthusiastic than when Justin Bieber was performing!  It was very reminiscent of G-Dragon's own concerts.

After his "Crayon" performance, G-Dragon said before leaving, "As Bieber will show you a better performance, I hope you will have fun until the end."

Justin Bieber took back the stage to continue his concert with "Out of Town Girls."

This special concert event became another form of proof that the two singers are close friends.  

Korea that was amazing. Thank u for the love. Shout out to my friend @IBGDRGN for coming out on stage tonight. They went crazy. #honored

— Justin Bieber (@justinbieber) October 10, 2013