Prince George, Princess Charlotte and Prince Louis will have to obey this royal wedding rule when they get married

The Cambridge children, Prince George, seven, Charlotte, five, and Louis, two, will all have to get permission if they want to marry when they are older.

• Young royal siblings Prince George, Charlotte and Louis must follow this protocol when it comes to weddings.
• The youngsters must obtain permission to marry when the time comes from the reigning sovereign.
• The rules come as Prince George and Princess Charlotte’s signatures seen for first time

The will have to follow in the footsteps of their dad Prince William and uncle Harry who both had to seek permission from the Queen before they could get married.

The rules apply because the young royals are all in line to the throne - Prince George is third in line, followed by Princess Charlotte who is fourth and then Prince Louis is fifth.

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As they are all currently above the sixth in line to the throne they are all bound by legislation which apply to senior members of the royal family, and should their position remain unchanged when they reach adulthood, it's understood they too will be bound by these marriage restriction laws.

Iain MacMarthanne told Express.co.uk, "Prior to the Succession of the Crown Act 2013 all descendants of George II, under the terms of the Royal Marriages Act 1772, unless the issue of a princess who had married into a foreign royal family, had to obtain the sovereign’s permission to marry in order to retain their rights in succession.

He continued, "The 2013 Act sought to bring multiple pieces of outdated and discriminatory legislation relating to the monarchy up to date."

Their father Prince William, 38, is second in line to the throne and he and his wife Kate, Duchess of Cambridge, 38, are future heads of the British Royal Family.

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While Charlotte and Louis' positions could slip further down the succession line, should Prince George one day have children, if this doesn't happen, they will all have to seek permission from the presiding sovereign when they marry.

Prince Harry also had to have his marriage to Meghan rubber-stamped before it could go ahead.