Description:Canadian singer Justin Bieber apologised via Twitter on Tuesday (March 5) after fans booed him for turning up nearly two hours late to a London concert, blaming technical issues for his late performance. The 19-year-old teen idol had been scheduled to take the stage at London's O2 Arena at 8.30 p.m. but said in a Twitter message that the time was pushed back to 9.35 p.m. due to "some technical issues".(0:44)