“It’s all in the timings of these things," Frost revealed.
“So we had Prince Harry telling a young audience ‘stay away from social media, it can damage your mental health, please live lives in balance and stop worrying about how you look'.
“Literally the very next day they launched their Instagram account. So I think there’s a little bit of management perhaps that needs to be improved."
Frost also questioned Meghan Markle's choice to post a black and white photo of baby Archie at his christening.
“This looks to me like old Hollywood days.
“When we didn’t expect so much of our stars, our celebrities, our royal public profiles."
The royal expert continued: “And now here we are, we have social media, we watch every twist and turn, we feel as a nation very invested.”
The Duchess was joined by senior members of the royal family - including Prince William, Kate Middleton, Camilla Parker Bowles and Prince Charles - for the private christening of her baby boy.
Meghan's mum Doria Ragland was also at the private chapel at Windsor Castle for the special ceremony, as well as the Princess Diana's sisters, Lady Jane Fellowes and Lady Sarah McCorquodale.
The Queen was unable to attend due to prior engagements.
Things are getting tense! Watch the moment Prince Harry tells Meghan off