The arrival of Kate Middleton and Prince William's third baby will not affect Princess Charlotte's succession to the throne.

The Succession to the Crown Act in 2013 stated that one's gender will no longer matter in his or her succession. "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)," the statement read.

According to BBC, the changes to the rules of succession were rushed through parliament ahead of the birth of Prince George in 2013. The former rules of male primogeniture stated that royal sons took precedence over their female siblings, including the firstborn royal daughters.

The act also replaces the Royal Marriages Act 1772 and means that only the first six in line to the throne need the Queen's consent to marry. This is the reason why Prince Harry and Meghan Markle still needed Her Majesty's approval prior to tying the knot. However, Princess Eugenie and other distant descendants of George II no longer need the permission of their grandmother to get married.

In related news, Princess Charlotte is already excited to be a big sister. In fact, she is looking forward to her younger sister or brother.

"William and Kate like to keep Charlotte involved and part of the excitement around having a new sibling," an insider said. "She's very aware she's going to have a new baby brother or sister."

In addition, Princess Charlotte reportedly plays with her dolls and pretends that they are babies. "So I think she is probably expecting the new brother or sister will be the same game — but in real life," the source added.

According to reports, Middleton is due on April 23. The Duchess of Cambridge will deliver her upcoming child in a luxury suite at the Lindo Wing of St. Mary's Hospital, where she gave birth to Prince George and Princess Charlotte in 2013 and 2015, respectively.

Meanwhile, Middleton is not freaking out with her third pregnancy despite reports claiming such. The Duchess of Cambridge has more help, and she and Prince William have already planned everything to the smallest details. "Everything is planned down to the tiniest detail," one insider said.

In fact, the royal couple has a baby team that is "dedicated to making sure everything is ready, from media plans to security to hospital arrangements. There's a backup plan for everything."