Royals fans can't help noticing that there's one recurring theme about Meghan Markle as she travels around Australia and the South Pacific on her first major overseas Royal Tour since marrying Prince Harry back in May.
Not her impressive array of jewels (though they are jaw-droppingly gorgeous, including gifts from the Queen, Prince Charles and gems that once belonged to her late mother-in-law, Princess Diana including that magnificent aquamarine cocktail ring).
Not her hair which has gone from down and sleek to her signature messy bun to up in a sleek chignon decorated with frangipani blooms in Fiji.
Not even her oh-so stylish wardrobe which has wowed crowds who've been impressed by Duchess Meghan's elegant choices from designers including Zimmerman and Jason Wu.
No, what's really got royal watchers talking is the one accessory that Meghan is never without and which she can't stop touching.
The Royal Baby Bump.
Since Harry and Meghan announced their baby joy to the world when they first touched down in Sydney at the start of the Royal Tour, the duchess has been spotted on numerous occasions tenderly cradling the merest hint that there's a bubba on board. And, according to pregnancy experts, there's one very good reason why.
Although Duchess Meghan, 37, has only just entered the second trimester of her pregnancy for her blue-blooded baby (due in the Northern Hemisphere Spring next year), and it's too early to be feeling the little one kick, it's likely she will be experiencing an overwhelming desire to protect her precious cargo. Not only this, but there will be small but distinct changes to her body of which Meghan will be only too well aware including fuller, more tender breasts.
WATCH: Look how sweetly Meghan cradles her baby bump on Fraser Island last week.
Story continues below...
"Although most women will start to feel their baby move by around 18-20 weeks, some women may feel this sooner," Lesley Gilchrist, co-founder of My Expert Midwife told the Daily Mail.
"Flutterings are the first sensations that are felt. However gas movement through the gut feels similar and this may cause an instinctive, involuntary touching of the stomach.
"It's not uncommon for women at a similar stage to the Duchess of Sussex to feel those sensations.
"Those feelings of your baby moving are extremely special for women. It is such an amazing time."
There have been plenty of babies for the royal couple to coo over on their 16-day, 72-engagement tour which may explain just why Meghan's rarely seen without a protective hand on her bump.
"There are many reflexes and primitive instincts that remain with us, as humans, today," Lesley explained.
"For many women they will be unaware that they are instinctively 'guarding' their baby.
"Many of those instincts are triggered when thoughts of their baby, sight of another baby and discussions of baby happen."
The first time the royal started to cradle her belly was during an official appearance in Sydney's Bondi last Friday when she sweetly placed her hand on her striped maxi-dress by Martin Grant.
Since then, Meghan hasn't stopped gently cradling her baby bump.
From Fraser Island to Fiji, this royal baby has been feeling the love from mum.
According to body language expert Judi James, Meghan's desire to constantly connect with her unborn baby demonstrates a strong bond between the pair and a keen desire to welcome her first child.
"We all know that Meghan's baby bump is still tiny, about the size of bump most of us would get following a large-ish plate of pasta, so it's especially revealing to see how keen she is to cradle it or hold it on her latest outings in Australia," James revealed to the Mirror Online.
Adding: "The one-hand cupping gesture combines hand-holding and touch with Harry with her new role as an expectant mum. Her public gestures with Harry often suggest a quasi-maternal approach of protection and reassurance and now she looks keen to spread that deeply caring affection to her unborn child.
"When she stands alone she tends to cradle her bump with two hands, which is an even more tender gesture of both pride and affection.
"It suggests she'll be a very tactile and hands-on new mother when the baby is born. When she's not bump-holding, her pregnancy is barely visible so these gestures also suggest her levels of excitement and impatience to have their first child," James concludes.
Looks like the duchess is going to be one very caring and protective mum to Baby Sussex!