Canadian-born singer Justin Bieber's My World Tour has been doing exceptionally well, according to reports.

Everything's been cool. Everything's been great, said DJ Tay James, Bieber's tour DJ, in an interview with MTV News, Absolutely ridiculous. I've been with him since his second show and just to see him do shows with 300 people to us doing [shows with] 50,000, it's crazy. I'm just happy to be in the position that I am. That's like my little brother.

Bieber's bassist, Alex Suarez, said that he was amazed not only by the size of the crowd but also by its enthusiasm.

Beiber's fans have flooded his concerts, welcoming him with open arms at each and every city he has performed in. What else could such a young artist, with so brief a history in the industry, ask for?

Bieber also surprised his fans in Rio de Janeiro, when his girlfriend and fellow singer, Selena Gomez appeared on stage, to perform briefly alongside him, STV reported.

Gomez performed her hit song Who Says and was joined by Bieber, towards the end of the song. That must have been a delightful treat to fans of both Bieber and Gomez.

Check out pictures of the concert.