NBC Universal, the company behind the TV hit, is footing the bill for the round-the-clock protection, because Meghan is not currently entitled to official royal protection - a service only granted to members of the royal family.
Although there is not understood to be a specific threat, the combination of her growing public profile and an awareness that Harry has claimed there have been social media attacks on Markle for her biracial heritage appear to have prompted to move.
The Prince revealed her passion for the Paralympic-style event for injured servicemen he set up three years ago when he met cycling competitors on Wednesday afternoon.'I asked him how his girlfriend was enjoying it and he said 'she loves it, she's loving the games,' which is awesome' said former US air force master sergeant Kyle Burnett, 37.
Harry and Meghan's relationship has been the source of much public interest during the week that he has been in Toronto for the sporting event; coincidentally the city is also the location of filming for Meghan's popular TV show Suits, and the prince is even said to have paid a visit to the set after arriving in Canada before the start of the games.
The brunette, who was dressed in a casual ensemble of a navy sweatshirt and jeans, appeared to be thoroughly enjoying her one on one time with the prince on Thursday.