Speaking to The Sunday Times, the Believe artist admitted that he has an obsession with keeping his fingers clean.
Bieber explained: "I hate getting sticky stuff on my hands. I've always had, like, a phobia - not a phobia.
"But if I get stuff on my hands, I have to have a washcloth to wash my hands because it's just so annoying."
Elsewhere in the wide-ranging interview, Bieber spoke about his fans' nickname for his genitalia.
Bieber also discussed how girlfriend Selena Gomez reacted to his paternity test scandal, following Mariah Yeater's false claim that he was the father of her child.
Watch Justin Bieber's 'Boyfriend' music video below: