Normally as a guest, especially a royal guest you are the one afforded special treatment.
For example if I have guests popping round I may remove the plastic toys/ trip hazards from the stairs and floors and hoover the crust of rice cakes from the carpet in the living room, if you're really lucky I might even wipe off some of the sticky handprints my entire house is now covered in.
But I probably won't.
(Top Tip Kate: avoid anything with a gloss finish when you have small children.)
A new baby trumps any guests, even royal ones.
All special treatment is diverted to the newest member of the family and guests must respect this and accept that standards in the home you are visiting may not be what they usually are.
So Your Majesty do not be surprised if you glance around the room and see William's underpants drying on the radiators.
This is quite normal.
As I write households up and down the land will be covered in drying washing. When there is no space left on the radiators your subjects will use chairs and small children standing still to hang things on, any available surface will do.
Anyone reading this from outside Britain may find this peculiar but this is the harsh reality of the British weather. There are only ever five days of the year when it is possible to dry washing outside. Homes in the USA have machines for the drying of clothes we Brits like to dangle our damp kecks over the backs of doors.
Don't ask why it is simply the British way.
Like teeth that look like actual teeth.
When visiting new parents it is totally acceptable for the hosts to be wearing leisure wear (Do Reiss do tracksuits?) or even, wait for it, their pyjamas.
This too is entirely normal.
As new parents it is hard to work out exactly where the day starts and night begins everything becomes a cycle of sleeping and feeding and when baby is not sleeping or feeding worrying about when they will sleep or feed next.
If that sounds exhausting Kate, don't worry my eldest is nearly three and we have stopped worrying about her sleeping and eating and now have completely new things to agonize about.
It is customary for guests to bring food. New parents often struggle to feed themselves as they are so busy with the aforementioned worrying.
Posh biscuits will do (speak to Charles) or if you have the time why not knock up a quiche Ma'am?
In most situations rocking up at someone's house and offering to bung the washing on would be seen as a little odd but as a family member visiting a new arrival it is customary to make an offer of help.
I would imagine that as an elderly family member with limited domestic experience Kate is unlikely to deploy you to unload the dishwasher (which, by the way, is a machine not a member of staff).
So you should get the butler to run you through the basics of folding washing and pairing up socks.
The baby may sleep for the entire time you are there, it is allowed to. No one should ever wake a baby up not even The Queen of England.
If the baby is awake remember these rules for the handling of a new born child.
First to hold the infant is the person who made it (Kate), next anyone else who contributed (William) and then the he or she is passed to the person sitting to their left.
It is rude to hog the baby! Be sure to pass it on to the person next to you.
You will probably want to bring a gift. This is not a time to start re gifting Maori canoes, if you really want to make an impact remember that bringing home a new born baby is terrifying and even more terrifying if that newborn baby is a future King or Queen of England and the whole world is watching you.
The best gift you could give Kate and Wills would be to divert the attention of the world's media.
And I have a suggestion (Don't worry no boats.)
Shove Suggs back up onto the roof and join in with Madness singing 'Embarrassment' to Harry.
That should do it.