According to a report, a private jet pilot has allegedly accuses Justin Bieber of boarding a plane while high on marijuana.

Editors at TMZ claim to have spoken to a pilot who recently took Bieber and his crew on an internal U.S. flight, and the unnamed aviator claims the star and his friends boarded the plane reeking of smoke which billowed from their van.

The pilot claims Bieber was "baked out of his mind" during the flight and was disorientated when crewmembers asked him to sign a credit card authorization form, although the star did not light up while on board.

The pilot compares the journey to Cheech and Chong's 1978 stoner movie Up in Smoke.

A representative for Baby singer has yet to comment on the report.

This is latest incident concerning Justin's 4/20 credentials, his pimp-out van was recently spotted with what looked a bong water being jettisoned from a window.