She has always been close to Kate - from providing moral support at the beginning of her relationship with Prince William to being her maid of honour at their wedding.
And now, Pippa Middleton is the favourite to become godmother to the couple's first child.
It's no secret that Kate
and William's younger siblings are two of the most important people in their lives, and both have been tipped to be offered godparent roles.
Joe Little, managing editor of royal magazine Majesty, said: "It is almost a foregone conclusion that they will be godparents.
"Pippa provided a heck of a lot of moral support when the couple began dating and during the brief period the couple separated. And William has always been very close to Harry following the death of their mother."
