King Charles has dished out a key role to his sister, Princess Anne, as a way of expressing his gratitude for her unwavering loyalty through the years.

Charles, who will make his first speech as monarch in Parliament Tuesday, has made Anne the Gold-Stick-in-Waiting — a role entrusted with the King’s personal safety.

She will serve as his personal bodyguard during Tuesday’s address to the UK government, the Mirror reports.

“This is a fantastic addition by the King and further cements the Princess Royal’s role as his most trusted lieutenant,” a source told the outlet.

On Tuesday, King Charles and his wife, Queen Camilla, will make the journey from Buckingham Palace to the Houses of Parliament in a Diamond Jubilee State coach, which carried them to his May 6 coronation at Westminster Abbey.

At the same time, Princess Anne will travel in a separate carriage behind them — a role she is reprising from the coronation, although she rode on horseback for her brother’s crowning.

The Gold-Stick-in-Waiting role dates back to the 15th century and would see the monarch protected by two rods made of gold and silver.

Once inside the House of Lords, Anne will accompany the monarch before he delivers a speech outlining the government’s legislative plans for the session ahead.

Anne’s new role means that if the King is taken ill or finds himself abroad, the Princess Royal is able to step in to take his place.

The Post has reached out to Buckingham Palace for comment.

King Charles’ former royal butler revealed how the King’s decision shows how he is “making the monarchy his own.”

Grant Harrold, who worked for King Charles for seven years when he was the Prince of Wales, said, “Anne has obviously been a Counsellor of State, which is who stands in for the King if he’s overseas or unwell — it’s quite an important role and he’s made it possible for Anne to stand in.”

“Anne would very much come to Charles’ aid without any question, but it’s more of a symbolic role, more than anything, and it’s a significant role because it shows how much Anne means to Charles,” Harrold continued.

Grant Harrold, who worked for King Charles for seven years when he was the Prince of Wales, said, “Anne has obviously been a Counsellor of State, which is who stands in for the King if he’s overseas or unwell — it’s quite an important role and he’s made it possible for Anne to stand in.”

“She will take this role very seriously and I think it shows how much the King is changing the monarchy and making it his own.”

Speaking on behalf of Spin Genie, Harrold added, “I’m sure there’s parts of Princess Anne that remind the King of his mother and vice versa, which is quite common in siblings.

“Anne was second in line to the throne, many, many years ago and I think what the King is doing is showing the family and his country, the Commonwealth, that his sister is a really important part of his household.”

After she was made the Gold-Stick-in-Waiting at her brother’s coronation, Anne told CBC News of what the position entails.

“I have a role as the Colonel of the Blues and Royals in the Household Cavalry regiment as Gold Stick [in Waiting]. And Gold Stick was the original close protection officer,” she told the outlet in May.

The princess rode on horseback behind Charles and Camilla’s carriage following the coronation ceremony at Westminster Abbey.

She led 6,000 armed services personnel through the streets of London in what is called the Coronation Procession.