The couple have revealed they will tie the knot on April 29 in Westminster Abbey - where Will's grandma Queen Elizabeth II was married in 1947.
According to The Mirror newspaper, the palace is bombarded with around 10,000 hate-mail letters a year, sparking fears of an increased risk of an attack, now the engagement has been announced.
The special security team will visit the homes of any would-be stalkers, and could even have those who pose a serious threat sent to a psychiatric ward.
An insider told the newspaper, "Sadly, the Royal wedding is likely to act as a magnet for the hundreds of people in Britain, and abroad who have an unhealthy obsession with the Royal family.
"Among them there is likely to be a small number who wrongly believe Prince William is destined to marry them and should not be marrying Kate."
Royal protection officers have been guarding the home of Kate's parents, Michael and Carole. The bride-to-be has reportedly been given a piece of jewellery fitted with a tracking device in case of any kidnap attempts.