Despite feeling ill, Justin Bieber didn't let his health problems get in the way of his New York Madison Square Garden concert last night (August 30).

The teen idol had already rescheduled his New York State Fair concert in Syracuse on Sunday night (August 29) due to ill health.

Just before taking to the stage, Bieber wrote on Twitter, "Ok the doctor said we aren't 100 percent but we are ready to ROcK!! Been cleared. MSG let's do this!!! Let's fill the streets of NYC!"

Today the singer has encouraged fans without tickets to try and get in for his concert tonight, by writing on Twitter, "Let's fill the streets of NYC with purple and even if you dont have tix we will be celebratin n maybe u might just find ur (your) way inside."