Earlier this week, it was alleged that the popstar behaved poorly on an American Airlines flight from Los Angeles to Asia, refusing to take his seat in preparation for take-off.
"He then gave the staff a really hard time the whole flight, nobody could believe it," a source told Fox 411. "And then at the end, the captain introduced himself to Justin and kindly asked for an autograph, and he rudely refused."
However, Bieber claimed that he has no knowledge of the incident, telling TMZ that it was fabricated.
"I have no clue. I have never heard that rumour," said Bieber. "I don't think you should believe everything you hear. People make up stuff all the time."
In May, CSI star Marg Helgenberger criticised the singer's behaviour on the set of the police procedural, claiming that he often acted childishly during working hours.
Bieber later defended himself from Helgenberger, insisting that the two had very little interaction on set.
Watch a clip of Justin Bieber in CSI below: