Justin Bieber slams Prince William for thinning hair: 'There are things to prevent that'

Justin Bieber is taking some heat for insulting the future King of England's thinning hair.

It's no secret that Prince William is, shall we say,  follicle-challenged.

Wills' bald spot has been spreading since he was 22 years old, but we're guessing he's had bigger things to worry about than his coif. You know, like preparing to rule a country.

"I mean, there are things to prevent that nowadays, like Propecia," Bieber told British mag Rollercoaster according to the Daily Mail. "I don't know why he doesn't just get those things, those products. You just take Propecia and your hair grows back. Have you not got it over here?"

Ouch.