While it might be fairly normal for parents to pick their siblings to act as godparents for their children, it seems this is not the case in the royal family.
Royal watchers have already started speculating, following the announcement that the Duchess of Cambridge was pregnant with her third child, who William and Kate will choose to be the godparents of baby number three.
Many might have hoped that Prince Harry would get a look in this time around, having not been chosen as a godparent for either Prince George or Princess Charlotte, but according to those in the know, anyone rooting Prince William's younger brother is set to be disappointed.
A royal expert has weighed in on the topic and explained why, despite playing an incredibly important part in the lives of his beloved nieces and nephews, Prince Harry won't be picked as a godparent this time either.
Royal expert Richard Fitzwilliams told the Express that in his opinion the 'emphasis could be firmly be on their close friends' when it comes to Kate and William's decision on who to pick as godparents for their new baby.
The Duke and Duchess of Cambridge chose to break with royal tradition when it came to selecting godparents for both George and Charlotte, as they picked close friends for the important roles, as opposed to just family members.
However, as well as choosing friends again this time, Richard thinks that William's royal cousins may have a chance at being chosen.
'It is possible Beatrice or Eugenie might be a godparent to the new baby,' he speculated.
Prince George's godparents include Julia Samuel, who not only is the founder patron at Child Bereavement UK - a charity that both Kate and William are passionate about and work very closely with - but was also one of Princess Diana's best friends.
George's godparents also include Jamie Lowther-Pinkerton who used to be the Prince William's Private Secretary.
Princess Charlotte has five godparents, as Kate and William clearly had a long list of people they wanted to honour by asking them to play an important role in their daughter's life.
Their friends Sophie Carter and James Meade are both godparents to Princess Charlotte, along with William's close friend Thomas van Straubenzee, and a cousin from each side of the couple's family. Prince William's cousin Laura Fellowes, and Kate's cousin Adam Middleton.