Fab Four
Expert explain why Prince Harry and Meghan Markle hold hands but Prince William and Kate Middleton, don't. Pictured: Prince William, Middleton, Markle and Prince Harry attend Christmas Day Church service at Church of St Mary Magdalene on Dec. 25, 2017 in King's Lynn, England. Getty Images/Chris Jackson

Meghan Markle and Prince Harry aren't shy when it comes to showing off PDA. In fact, when they made their first public appearance as a couple, they were holding hands. But are they breaking any royal protocols by doing this?

The Duke and Duchess of Sussex have been very affectionate towards each other even during royal events. According to royal etiquette expert Myka Meier, they held hands to celebrate their engagement. "While Prince Harry and Meghan holding hands is a typical for royal engagements, it is a seemingly welcomed gesture to show unity and celebration of their engagement period," Meier said (via Daily Express).

She added that there is no rule forbidding royals from avoiding PDA when they are attending official engagements. In fact, doing so makes them "relatable and loveable to the public."

However, unlike Prince Harry and Markle, the Queen and Prince Philip, as well as Prince William and Kate Middleton, rarely hold hands in public. These couples are very careful with their gestures when in the crowd.

"The Queen rarely holds hands with her husband in public and this seems to have set an unwritten precedent for the other royals," body language expert Robin Kermode said. "It is very clear that William and Kate are emotionally close, however, they do not seem to feel the need to prove their love – particularly when on official state business."

Although the Duke and Duchess of Cambridge don't pack on PDA as often as Prince Harry and Markle do, there have also been seen subtly touching each other in public. For instance, Prince William and Middleton held hands while walking towards the church to attend the Christmas service in Sandringham back in December.

When they attended St. Patrick's Day parade in March, Middleton, who was heavily pregnant with Prince Louis at the time, and Prince William also subtly showed their affection for each other. The prince was photographed placing a hand on his wife's back.

Meanwhile, last week, Prince Harry and Markle joined Queen Elizabeth II at the Queen's Young Leaders Awards ceremony. According to reports, the new duchess reached out and tried to hold her husband's hand, but Prince Harry apparently ignored her efforts. Instead of reaching out to grasp Markle's hand, he brought his arms together near the center of his body and they walked on as if nothing happened.