In case anyone was in any doubt, Prince William is starting fatherhood as he means to continue it - having already changed his son's first nappy.
William - looking happy and relaxed as he and Kate brought the new babe out to the waiting world - revealed that he personally had already changed the nappies of Britain's newest royal.
It's the clearest sign yet that William is planning on being a quite different kind of Royal dad to any that we have ever seen before.
I'd be prepared to wager quite a large sum of money that William is the first direct male heir to the throne ever to have changed a nappy in HISTORY!
Can you imagine Prince Charles ever changing a nappy? Or the Duke of Edinburgh? These were royals from a very different age - and William is intent on showing that he is going to be a very different type of Royal dad.
A few minutes later, William was strapping the baby's car-seat into his car. He then jokily wiped the brow of his head, as if to show that this was another rite of dad-hood that had passed off without a hitch.
These may be small things in themselves, but they reveal much about how William and Kate plan to bring up their baby.
Instead of leaving the nappy-changing to a midwife - or even his own wife - William was (literally) rolling up his shirt-sleeves and getting stuck straight in. And, speaking from experience, those first couple of nappies are... something else.
Then, as they were leaving the Lindo Wing of St Mary's Hospital, Paddington, it would have been all too easy to have left the tricky business of strapping in the baby's car-seat to the bodyguard. But no - William was insistent on doing the job himself.
It went off without a hitch. He must have practised quite a bit beforehand.
It was also telling how William and Kate chose to celebrate the new arrival - by sending out for a couple of pizzas.
While the world was going mad for the Royal baby on Monday night, William and Kate were gazing at their baby and happily munching on pizza - just like any other new mum and dad.
It'll be interesting to see how long William and Kate can carry on being the hands-on parents that they hope to be. They're planning to bring up the baby by themselves with just the occasional call out to Kate's mum for the odd bit of baby-sitting.
Well... it's a wonderful dream. I hope they can manage it.
But one of the few titbits that William did reveal about his new son is that the wee boy has a strapping set of lungs.
Give William and Kate a few months of sleepless nights and - like any other new parents - they'll be on their knees for reinforcement.