Singer Justin Bieber gave the director of his latest music video a scare after turning up on set with blinding bling in his mouth.

The 17-year-old pop star had some fun while shooting the promo for his festive single Mistletoe after pranking director Roman White by placing a sparkling dental grill over his teeth.

White tells MTV.com, "We were about to start shooting the first scene, and he was walking around, and he had this grill in the bottom of his teeth. It was bedazzled like you wouldn't believe.

"He kept walking by me and just smiling a little bit so I would see it. I think he was trying to stress me out, because he knew that I wasn't really going to want him to wear this glittery grill on the bottom of his teeth. And finally, I was like, 'We're not going to wear that, are we?'"