If it's not one thing, it's another.
Traditionally the role goes to a friend or family member, which puts the princess-to-be's sister Pippa Middleton at the top of the list.
However, Kate could also do what Princess Diana did and select someone who has a royal service background.
Author Judy Wade explains:
"Diana didn't use her sisters until years into the job. Up until then she had someone who was steeped in the royal background, and Kate might do the same. If Pippa does do it, it will likely be on a part-time basis."
For the time being, Kate has been using Helen Asprey, an assistant from Prince William and Prince Harry's office.
[Image via Zak Hussein/WENN.]