Why Archie's polo outing with Meghan surprised everyone

Baby Archie has made his first public appearance, attending the polo with his parents the Duke and Duchess of Sussex.

The two-month-old’s presence caught many off-guard, with experts never expecting the youngest member of the British royal family to be seen so soon after his birth — especially in light of the decision by Harry and Meghan to keep their son's christening on July 6 a private affair.

"It was a surprise to see baby Archie. I think a lot of us royal watchers thought the next time we were going to see him was when he graduated from university," royal commentator Duncan Larcombe told Today.

But there was one clue from Buckingham Palace in the leadup to the polo that hinted at a possible special appearance of someone – other than William and Harry – at the event.

"The palace was very tight-lipped," Larcombe says. "These polo matches are covered by large groups of photographers all throughout the polo season. But mysteriously, about three or four weeks ago, when the photographers that usually cover these were trying to get accredited to be able to go in and take pictures, there was a massive restriction on the numbers.

"There really weren't very many [photographers] allowed in today, so we kind of knew in advance that it wasn't just William and Harry that were going to be playing.

"We reckoned there were going to be a few of the rest of the family but I don't think anyone expected to see Archie and to see the Cambridge children there all playing together happy families – a long overdue show of solidarity between them all."

Larcombe says the appearance by both the Cambridges and the Sussexes was "carefully orchestrated" to put rumours of a royal rift to bed.

Photos from the polo show the Duchess of Cambridge, and her sister-in-law Meghan, the Duchess of Sussex, smiling and laughing while their children play nearby.

"We know Kate, the Duchess of Cambridge, is a real hands-on mum and I think we saw the first glimpse of what Meghan's going to be like – very affectionate towards baby Archie and I actually think it was quite nice to see all the children and the wives all there enjoying a day out in the sunshine," Larcombe says.