Prince William PIC: Richard Pohle/The Times/PA Wire

Pop heartthrob Justin Bieber has caused a right royal stir by urging Prince William to start using hair loss products.

The 18-year-old Canadian star - famed for his lustrous locks - was mystified when asked why Prince William had not taken action against his thinning hair.

“I don’t know why he doesn’t just get those things, those products?” asked a horrified Bieber.

“You just take Propecia and your hair grows back.

“Have you not got it over there?”

It remains to be seen whether Prince William will act on Bieber’s not-so-tactful advice, but with his busy Olympic schedule kicking off with the opening ceremony this evening, the future king won’t have much time to worry about his hair over the next couple of weeks.

Loyal Beliebers, meanwhile, can rest assured that their hero’s hair has a long life ahead of it.