American teen girl heart-throb Justin Bieber is planning a Halloween surprise with a customized diamond grill to cover six of his teeth.

The so-called diamond grill is being made for the 17-year-old If & Co which specializes in making jewelry for celebrity customers.

Few details are available about the grill and how much it is worth, but given that Bieber's personal fortune is estimated at more than $100 million, it is not likely to be of concern to the singer.

If & Co makes customized jewellery for many celebrities, including Paris Hilton, Kim Kardashain, Tom Cruise and Drake.

The designer of the diamond grill, Ben Baller, tried to reassure Bieber's many teeny fans that their hero was not planning to keep the diamond grill on his teeth over the long term with an announcement on his website: "To all the billions of Justin Bieber fans – I do NOT make permanent grills, I only do the ones that are removable, you can put them on and take them off within seconds and they're for fashion and fun. Relax, your little heart throb is not ruining anything."