Piers Morgan says ill feeling between the Fab Four "runs very deep".
Prince Harry, Meghan Markle, Prince William and Kate Middleton reunited following the death of the brothers' grandmother Queen Elizabeth II.
Her Majesty died in Balmoral on Thursday (September 8) surrounded by her family who desperately raced to her side in her final hours.
The nation is in mourning and members of the Royal Family, including the 'Fab Four', recently came together to meet the grieving crowds.
Former Good Morning Britain presenter Piers penned his thoughts about the ordeal in his most recent column for the New York Post.
"Don’t be misled by the scenes of supposed hatchet-burying between William and his brother over the weekend," penned the 57-year-old TV presenter.
"That was a show of forced unity to wrestle media attention away from their rift to their grandmother in the run-up to her state funeral next Monday."
He added: "All you need to know about how deep their split goes is that when Harry went to Balmoral as the Queen died, and stayed until the following morning, he reportedly had no contact with William the entire time despite them being in the same building."
Piers says that their "temporary truce" was a "mark of respect for their grandmother" and would have been something Her Majesty "desperately wanted".
Despite this, he says he is "not fooled by it" and that "the depth of ill feeling between them, and their wives, runs very deep".
Piers later went on to dub Harry and Meghan "whiny money-grabbers" after causing "havoc" within the Royal Family.
He added: "Queen Elizabeth II espoused values of honesty, integrity, decency, stoicism, resilience, duty, service, humility and selfless devotion to her country.
"How does any of that compare to the selfish, whiny, money-grabbing and damaging way Harry and Meghan have conducted themselves since then?"
"Their hypocritical exploitation of their royal status for vast personal financial gain, while simultaneously trashing the institution that bestowed their titles upon them, caused enormous hurt to the Queen in her last few years," he penned in the NYC newspaper.
"Especially during the period when her husband, Philip, was seriously ill and then died, and to the new king," he added.
Last week, following the news of Queen Elizabeth's death at 96, Piers was one of the first celebrities to pay tribute to the monarch.
He described the Queen as "dignified, humble, wise, stoic, and dedicated to duty and service to the country she loved", as well as the "greatest monarch in history and the greatest of Britons".
The Daily Mirror and Sunday Mirror celebrate the life of Her Majesty the Queen with a commemorative special filled with all the key moments from Britain’s longest reigning monarch. Be sure to pick up your copy of the Daily Mirror and Sunday Mirror to get both pullouts.
