Princess Charlotte is making an important royal "first" following the birth of her brother.

With the birth of a new royal prince, Princess Charlotte is making history as the first princess who doesn’t have to surrender her position in line to the throne to her younger brother.

Previously, royal sons took precedence over their female siblings, even leapfrogging first-born royal daughters to become king. Prince Andrew, for example, is the Queen and Prince Philip’s third child, but when he was born in 1960 he overtook his older sister, Princess Anne, in the line of succession.

But the Queen – like the boss she is – introduced a radical shake-up of the royal succession rules and removed discriminatory male bias in 2015, affecting babies born after October 28 2011.

That means the new little prince is no longer allowed to jump ahead of older sister Princess Charlotte, who is now two, in the line to the throne.

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The new prince is unlikely ever to be crowned sovereign, really. First it will be his grandfather Prince Charles, then his father Prince William, before his brother Prince George, his sister Princess Charlotte, and then himself.

Poor old Prince Harry, of course, has now been bumped to sixth place.

Princess Charlotte and her four-year-old brother Prince George went to visit their mum, the Duchess of Cambridge, in hospital this morning, where they met their new baby brother for the first time.

The prince was born at at 10.01am and weighed 3.8 kg.

Prince William, Duke of Cambridge arrives with Prince George and Princess Charlotte at the Lindo Wing after Catherine, Duchess of Cambridge gave birth to their son. Image via Getty.
Image via Getty.

With AAP.