(Cover) - EN Showbiz - Justin Bieber was tackled to the ground by an undercover officer during an appearance at Macy's, according to reports.

The teenage singing sensation was at the New York superstore on Thursday to launch his new fragrance Someday. The 17-year-old Canadian star was heading outside to greet fans, when according to witnesses; a man leaped over the metal barrier and tackled him to the ground.

It has now been reported by American website TMZ that the plainclothes officer jumped to save Justin from the overzealous crowds, but the singer's security didn't realise the man was a policeman, and jumped to his defence. A member of Justin's security team pulled the man off the young star.

Justin didn't know the man, who was dressed as a civilian, which apparently made him defensive.

TMZ reports that after the cop identified himself he then "cited" the security team member for "disorderly conduct".

Justin wasn't injured in the scuffle and continued signing autographs for his fans outside once the situation was brought under control.

This isn't the first time Justin has caused mass hysteria. His Australian show at Sydney Harbour was cancelled last year over concerns for the safety of fans, because of over-crowding. (C) Cover Media