Columnist Sarah Vine added: “They sort of straddle the world between royal, one foot in showbiz and one in royalty and they sort of feed off each other.
“Everyone’s going to be interested in what Meghan’s wearing, whether she’s got nice jewellery on.
“All the same rules that would apply to any celebrity.”
The couple will head to Manchester for the One Young World Summit, an event which brings together young leaders from more than 190 countries, on September 5.
Meghan, a counsellor for the organisation, will give the keynote address at the opening ceremony.