Prince William, Kate Middleton Show Rare PDA During St. Patrick's Day Parade

Prince William is being extra supportive to his pregnant wife, Kate Middleton.

The Duke and Duchess of Cambridge rarely show PDA. In fact, unlike Prince Harry and Meghan Markle, they hardly touch each other or hold hands when in public. However, the royal prince broke this on St. Patrick's Day parade.

Express shared a photo of the father of two, giving a reassuring hand on Middleton's back. Upon seeing the snap, a number of royal fans were reminded of Prince Harry and Markle. The "Suits" star and her fiancé are not shy in showing their affection in public.

In fact, when Prince Harry and Markle made their first appearance as a couple in the Invictus Games in Toronto, they were photographed holding hands. They have been doing this on multiple occasions already which set them apart from Prince William and Middleton.

However, although the Duke and Duchess rarely touch each other when in the crowd, there were times when they couldn't keep each other's hands off of each other. For instance, Prince William and Middleton were photographed holding hands while walking last December to attend the royal family's traditional Christmas morning service.

On the same month, weeks before the holidays, Prince William and Middleton appeared on BBC's "Blue Peter." During the interview, many were surprised when the Duchess touched her husband's knees as they playfully joked around.

Aside from this, Prince William and Middleton showed their sweetness in a Christmas portrait that they presented to the king and queen of Norway. Chris Jackson, the photographer who captured the snap, shared it on Instagram.

In the photo, Prince William and Middleton are all smiles as they wrap their arms around each other. Their fans who saw the photograph were very pleased as it reminded them of how affectionate the couple was before they got married.

"I think it's the most 'real' photo of Kate & William. They are so in love, and it's nice to see true affection and happiness between them," one user commented.

"One of the best pictures I've seen in awhile... reminds me of their engagement photos... " another follower added.

Prince William and Middleton are celebrating their seventh wedding anniversary on April 29. According to the Duchess of Cambridge, she is "lucky" to marry Prince William.

"I'm very, very lucky. [William] looks after me as much as possible," Middleton told Colonel Robert O'Brien.