Pop star Justin Bieber has thrown himself into the ring for a bloody new boxing-themed photo shoot that is sure to shock his fans.

The Baby hitmaker covers the April/May issue of Complex magazine and, in the alarming spread, Bieber can be seen sporting a battered face, bloody nose and soiled white tuxedo.

Meanwhile, an alternative cover features a swollen-lipped Bieber nursing a black eye with a slab of raw meat and inside, the normally-fresh-faced singer is snapped taking a punch to the jaw and spewing a mouthful of blood.

The controversial shoot, which is touted as the publication's 10-year anniversary "knock-out special edition", was reportedly inspired by the pop star's ability to "roll with the punches".