Prince Charles, his son Prince William and their respective spouses — Camilla, Duchess of Cornwall, and Kate Middleton — were seen sharing a joke during a carriage ride Monday.

Looking very regal, the heir to the throne and his son were clad in their velvet robes, resplendent for the Order of the Garter ceremony at Windsor Castle.

Their ebullient mood was on show for all to see only hours after disgraced Prince Andrew, Charles’ brother and William’s uncle, was banned from the event. It was a decision made by Charles and William, according to royal sources, and left to the Queen to tell her middle son.

Now, royal watchers and insiders are speculating that the move signifies a power shift in the family.

“It’s interesting because the Queen seems to protect Andrew a lot, so maybe this is a sign of the next generation coming into power,” one well-placed royal source told The Post. “It was surprising to me that Andrew was going to be involved to begin with, not that he actually got uninvited.”

Another palace insider pointed out: “Before, it was very much William and his brother, Prince Harry, as a team. Now … with Harry and William not in a great place, William and Charles seem to be the new team. They have to rely on each other.”

One intriguing thing, the source added, is that following the Platinum Jubilee, it appears that Charles, Camilla, William and Kate may well share responsibilities moving forward. Kate and William and their three children were front and center during the four-day extravaganza.

And it was the Cambridges who were back on the scene in the days afterward. Kate, 40, made a visit to Little Village, a baby bank network, while William — who turns 40 on June 21 — was last week pictured undercover on the streets of London selling copies of The Big Issue magazine, which profits the homeless.

“That seemed pretty clear to me that the four of them are going to ensure a successful and smoothed-out transition once Charles takes the throne,” said the royal source.

Andrew’s name was already printed in the program for the Garter ceremony by the time the palace announced there would be no public role for the royal, who lost his HRH titles and all military responsibilities over his ties to pedophile Jeffrey Epstein and a sexual assault lawsuit by Virginia Roberts Giuffre.

Buckingham Palace told The Post it was a “family decision” to stop him from making any public appearance.

Instead, Andrew — who continues to wear a jacket with the Grenadiers’ motto, “Shame on him who thinks evil of it,” when out horse riding — was later seen arriving in his Range Rover at Windsor Castle for the investiture and lunch, behind closed doors. Despite remaining a member of the Order of the Garter, he was seen in a suit and tie.

Andrew had already missed out on any Platinum Jubilee celebrations after it was announced that he had contracted COVID, although some were skeptical if that was a convenient excuse to keep him out of sight.

But then came the news that Andrew was keen to return to public life.

As The Post revealed back in December, despite being caught up in a civil suit against Giuffre, Andrew wanted to be back “serving his country, carrying out his public duties.” But as a source who knows him admitted at the time, “This won’t be easy.”

Over the weekend, the Telegraph reported that Andrew had subsequently tried to take his first steps back to the royal fold, including asking for his colonelcy of the Grenadier Guards back.

A source told the outlet: “The colonelcy of the Grenadier Guards was his most coveted title and he wants it back. Having remained a Counsellor of State, he also believes he should be included at royal and state events.

“Most importantly for him is his status as an HRH and ‘Prince of the Blood’ and he feels that should be reinstated and his position recognized and respected.”

In February, Andrew and Giuffre reached a settlement in her sex abuse lawsuit against him — sparing potentially embarrassing details about the embattled royal from ever being made public.

The sum of the settlement will not be publicly disclosed, according to papers filed in Manhattan federal court. But a source told The Post the estimated total is $12 million.

At the time, Joe Little, managing editor of Majesty magazine, told The Post that although Andrew had never been convicted of any crime, “There is no getting around the fact his reputation is badly tarnished, and in the process it has also tarnished the institution of the monarchy. A lot of damage has been done.”

Asked about any move back to public life for Andrew, royal author Hugo Vickers told The Post Monday, “It’s all too soon.”

Despite everything, the 96-year-old monarch remains in charge. Relying on a cane, the Queen still carried out the formal investiture of the new Garter knights, including former Prime Minister Tony Blair, plus attending the lunch with the current Knight and Lady Companions.

Camilla was also made an esteemed Royal Lady of the Order of the Garter by her mother-in-law.