Some fan watchers believe Baby Sussex has already arrived in secret.
WATCH this video to find out why!
The Sussexes already confirmed they are keeping the details of their birthing plan private, with Meghan shunning the royal tradition of a delivery at the exclusive Lindo Wing of St Mary's Hospital in London.
The couple also confirmed they will announce the birth with a photo call inside the grounds of Windsor Castle via a statement from Buckingham Palace.
But whether the royal baby is already amongst us or not, one things for sure: it's highly unlikely that William will miss any major moment regarding his little brother's first born child.