The Prince and Princess of Wales's youngest son Prince Louis is yet to reach one major milestone.
Unlike his two older siblings, Princess Charlotte and Prince George, Prince Louis hasn't joined his parents on a royal tour.
© Getty ImagesHis two older siblings Princess Charlotte and Prince George have already hit this milestone, travelling in tow with their parents on numerous international tours. Back in 2014, George travelled to Australia and New Zealand with his parents, while in 2016, Charlotte had a spotlight moment when she joined William and Kate in Canada.
© Getty ImagesA potential tour may soon be on the horizon, however, with Princess Kate recently revealing her wish to take her children to Australia and New Zealand now they are a bit older.
During a trip to Wellington Barracks on Monday for the St Patrick's Day Parade, the royal mother-of-three said: "George finds it fascinating that he has been to Australia and New Zealand.
"I would like to go back there with them now. It's finding the time to do that. But I love to travel – yes, it's a long flight. But I love the Middle East because that's familiar to me [from] growing up. There are so many opportunities now to travel, I think it's brilliant to experience it."
© Getty ImagesShe continued: "We tend to go further afield when it’s official visits, it's being able to carve out time to experience these countries in a more private capacity. Because otherwise you end up seeing lots of insides of amazing buildings, but you don't get to meet that many people."
The British royals must adhere to an array of strict rules when it comes to royal tours. Crucially, they must always bring a black outfit in case a monarch dies. This rule was brought in when the late Queen was caught foul of it in 1952, following the death of her father, King George VI.
Beyond this, they must also travel with a doctor who is expected to pack blood bags that match the monarch's blood type in case of an emergency.
Back in February, the Wales clan enjoyed a family holiday on the Caribbean Island of Mustique where they also reportedly celebrated Carole's recent milestone birthday.
© Getty ImagesThe Mail on Sunday reported that they made use of the opulent villa, Les Jolies Eaux, gifted to the late Princess Margaret back in 1959. The tropical bolthole boasts five bedrooms, stunning sea views, a private plunge pool, a butler and a gardener.
Perhaps unsurprisingly, the Caribbean pad costs a whopping £37,000 per week!
