Troubled pop star Justin Bieber is sporting a new tattoo after undergoing an inking session on a plane.

The Baby singer had the word 'forgive' inked on his stomach during a flight on a private jet to Canada.

Pictures of the session with celebrity tattoo artist Bang Bang have been published on and show the 20-year-old star lying on a bunk in the jet's cabin as he goes under the needle.

Bang Bang, real name Keith MCCurdy, tells the process was tricky due to turbulence, adding, "(It was) the most difficult tattoo I've ever done for sure."