Uncle Prince Harry and aunt Meghan Markle were all smiles in their new nephew, Prince Louis' christening portraits

Uncle Prince Harry and aunt Meghan Markle were all smiles in their new nephew, Prince Louischristening portraits, which were released on Sunday.

The royal newlyweds appeared in two of the four portraits, which were taken in the Morning Room at Clarence House (grandpa Prince Charles and Camilla, Duchess of Cornwall‘s official London residence).

In one of the photos, Meghan snuck in their signature couple move when she looped her hand through Harry’s arm.

Seated (left to right): The Duke of Cambridge, Prince George, Prince Louis, The Duchess of Cambridge, Princess Charlotte. Standing (left to right): The Duchess of Cornwall, The Prince of Wales, The Duke of Sussex, The Duchess of Sussex.
| Credit: Matt Holyoak/Camera Press/REDUX

Since they made their very first appearance together at the Invictus Games last September, the royal couple has held hands, rubbed each other’s backs and linked arms in public — moves almost never seen by other members of the royal family.

“While Prince Harry and Meghan holding hands is atypical for royal engagements, it is a seemingly welcomed gesture to show unity and celebration of their engagement period,” royal etiquette expert Myka Meier, founder and director of Beaumont Etiquette, tells PEOPLE. “There is no protocol that says they can not show affection on official engagements, and this gesture makes them relatable and lovable to the public.”

Prince Harry and Meghan Duchess of Sussex Attend Summer Party at the British Ambassador's Residence
Meghan Markle and Prince Harry
| Credit: PA Images/INSTARimages

Meghan and Prince Harry holding hands at a royal engagement is a refreshingly modern approach to their new role both as a couple and as representatives of the royal family,” she continues.

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Harry and Meghan’s open affection is indeed a departure from usual royal behavior. A certain decorum tends to be the norm when it comes to official royal outings. Will and Kate, for example, rarely show PDA.

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Prince William, Meghan Markle and Prince Harry
| Credit: Jeff Spicer/Getty Images
Prince Harry and Meghan Markle engagement announcement, Kensington Palace, London, UK - 27 Nov 2017
Prince Harry and Meghan Markle
| Credit: Shutterstock

“It is rare to see royal couples holding hands on official outings,” Myka adds. “While we are much less likely to see The Duke and Duchess holding hands in public, we often see Prince Charles and The Duchess of Cornwall holding hands – it’s all simply a matter of preference for each couple and is also likely dependent on the nature of the event they are attending. A more serious engagement would warrant a more serious level of professionalism, which each royal is sure to follow.”

However, Harry and Meghan refrain from holding hands when they are in front of Queen Elizabeth. Queen Elizabeth and Prince Philip never show affection in public. Despite their closeness (70 years of royal marriage!), they are never seen holding hands in public due to the “stoic values” of their generation, royal biographer Gyles Brandreth told PEOPLE.