The British royals made headlines in September of last year with the announcement that Kate Middleton and Prince William were expecting their third child.
According to the Succession to the Crown Act 2013 (which was passed once Kate was pregnant with Prince George), if the Duchess of Cambridge gives birth to another boy, Princess Charlotte will be the first female royal in history to not lose her spot in line for the throne.
The new rule, which applies to all royals born after October 28, 2011, dictates that succession be based fully on birth order instead of gender.
Currently, Prince Charles is the heir to the throne after Queen Elizabeth II. Prince William falls in second place, with Prince George and Prince Charlotte sitting in third and fourth positions, respectively.
Prince Harry (who was recently spotted with Meghan Markle at the Invictus Games trial this weekend) is currently fifth in line to the throne but will move down a spot after the arrival of the new royal baby.
Kate Middleton is due to give birth later this month so make sure to watch this space for more information.
Also, read about how Kate Middleton became the first royal patron of the V&A Museum.