The two-year-old is set to make history when her new sibling arrives thanks to the Succession to the Crown Act of 2013.
According to The Sun, Charlotte will become the first female royal to retain her claim to the throne, regardless of whether the Royal baby is a boy or a girl.
Meaning that a female royal’s claim to the throne is no longer diminished by the arrival of a younger brother.
“In determining the succession to the Crown, the gender of a person born after 28 October 2011 does not give that person, or that person’s descendants, precedence over any other person (whenever born),” it states.
The previous 701 succession act stated that brothers would always come before their sisters when it came to who was first in line to the throne.