There are lots of rules royals have to follow on royal tours.
Their clothes must be carefully selected to respect different cultures, and two royal heirs should not travel together.
There’s a list of foods they can’t eat on royal duties, including shellfish and rare meat due to the risk of food poisoning.
Royals are even told to bring a spare black outfit on tour with them, just in case a member of the royal family dies when they are away.
Kate Middleton and Prince William are known for bending the rules - with Prince William continuing to travel with his son, Prince George, who is third in line to the throne after him.
But there’s one thing they are strictly banned from doing.
William and Kate aren’t allowed to accept gifts from members of the public, and they are not permitted to sign autographs.
For security reasons and risk of forgery, the Duke and Duchess are banned from signing anything.
This must be particularly hard for the Duchess, who has been known to pose for selfies in the past. But if asked for her signature she must respectfully decline.
It's a rule other senior members of the royal family must also follow, including Prince Charles, Prince of Wales.
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According to The Express, the Queen's eldest son reportedly responds to autograph requests with: “Sorry, they don’t allow me to do that."
But he did break protocol back in 2010 when he signed an autograph for a victim of devastating floods.
He scrawled “Charles 2010” on a piece of paper, but has done nothing of the sort in all the years since.
