It’s been a tough night and day for teen pop singer Justin Bieber.

After being embarrassed by a very unfunny David Letterman last night on his show, an unidentified man attacked Bieber on the street outside of Macy’s store in Manhattan’s Herald Square.

The young Canadian was attending an event in Macy's to promote his new cologne, and then decided to go outside to meet some fans.

However, as soon as he emerged into the sunlight, an unidentified man jumped over a barrier and knocked the singer to the ground.

Bieber was not injured in the attack, while the assailant was taken away by police.

One witness told a New York TV station: I see that guy going around, but I didn't think anything about it, but all of a sudden he just jumped...Three guys were holding this guy back.”