He reportedly went against doctors' order by going ahead with his show in Brisbane on Tuesday (26Apr11), and subsequent reports suggested the singer was on the verge of cancelling Thursday's concert in Sydney.

But Bieber proved the rumours wrong by taking to the stage at the city's Acer Arena as planned and he gave fans an extra treat by bringing on his Next 2 You collaborator Brown for a joint performance.

In a post on Twitter.com after the concert, Bieber writes, "And they thought we might cancel tonight. Look at me now! I love Australia!"

Brown adds, "The show tonight was craaaaaazzzzzzyyyyyy!!!! Justin Bieber... shut it down."