Princess Diana's former bodyguard talks security at Meghan Markle and Prince Harry's wedding (exclusive)

Security will definitely be a top priority when it comes to Meghan Markle and Prince Harry's feverishly anticipated wedding, the late Princess Diana's former bodyguard, Ken Wharfe, tells ET.

ET spoke to Wharfe -- a former protection officer to Diana as well as her sons, Prince William and Prince Harry -- on Thursday. According to Wharfe, police will make sure nothing is overlooked for the massive occasion, and no expense will be spared.

"From my own experiences -- and speaking to colleagues within the last few weeks -- Scotland Yard and neighboring police forces that will be part of this operation will be only too aware of how important it is to make sure that no stone is left unturned, and you know, one talks in this day of austerity of finance," he says. "Trust me on this occasion, finance has nothing to do with this. Scotland Yard, together with Thames Valley Police -- which will be policing this event -- money is not an object, and they make sure that the very best of security is put on display to make sure that security is not compromised."

Meghan and Harry are set to marry on May 19 at Windsor Castle in London, England. ET learned on Thursday that the two faced an anthrax scare last Monday, when a white substance was sent in an envelope addressed to the couple along with a threatening letter, which a source told us had "racist overtones." The substance was tested and determined not to be anthrax, and Metropolitan Police are investigating the letter, which is being treated as a racist hate crime.

"I think the very fact that such an incident's happened, and this package has been received, I think it sort of sends out a message, certainly to the security services ahead of the wedding in May," Wharfe tells ET. "And, you know, one has to be very alert, given the fact that Harry and Meghan are very high-profile individuals, and for the vast majority of people in the world, receiving messages of great joy and comfort. But in this world we now live in, we have ... what we call 'fixated individuals' that are determined in some way or another to corrupt that goodness. The great thing is that this package was found, which proves the security... issues that are in place are working."

Wharfe is confident that security will be top notch at Meghan and Harry's nuptials.

"With all the expertise and using all the templates of William's wedding, and other weddings in the past, the security there will be massive," he stresses. "As I said five years ago, when William was married, that I do not forsee any problems at all. There will be sort of fringe demonstration, perhaps, for those that are Republican that perhaps don't like the idea of a royal wedding, but the police are well versed in this and will use their experience over many, many years to ensure that the happy couple have a great day."