According to Express, a spokesperson for the couple confirmed the couple laid flowers from their personal garden on the graves of two Commonwealth soldiers.
"It was important to the Duke and Duchess to be able to personally recognise Remembrance in their own way, to pay tribute to those who have served and to those who gave their lives,” the spokesperson said.
“My god, they've even turned Remembrance Sunday into another self-publicity stunt. Have they no shame?” Piers wrote on Twitter.
In a follow-up post, he added: “Just outrageous - treating Remembrance Sunday like a PR opportunity, & trying to steal headlines from the real royals doing their duty back home."
Royal commentator Dan Wootton then weighed in on the couple's appearance, pointing out how convenient it was a photographer just happened to be at the cemetery.
“How lucky that a photographer happened to be here to capture this deeply personal moment,” Dan wrote.
While the sentiment of some fans echoed that of Piers and Dan, many took to the social platform to congratulate Harry and Meghan for taking part in the British tradition.
“Lovely to see them today paying their respects and such a shame it wasn't at the cenotaph in London. Keep up the good work Harry & Meghan,” one fan wrote.
Another person stated: “True representatives of British honour - Harry and Meghan, always!”
Meanwhile, a third fan added: “Well done Harry. Your service and commitment to the military and all its members is unwavering.”
Harry, who spent 10 years in the armed forces, only recently described Remembrance Day as "a moment for respect and for hope", while speaking on the Declassified podcast.
"The act of remembering, of remembrance, is a profound act of honour,” the 36-year-old began.
“It's how we preserve the legacies of entire generations and show our gratitude for the sacrifices they made in order for us to be able to live the lives we live today."