It's set to be a big day in the Prince and Princess of Waleses' home tomorrow - the birthday of their youngest child Prince Louis.
The cheeky youngster is set to turn five and there's no doubt Prince William and Kate will do all they can so Louis has a day to remember.
And there is one sweet tradition Kate carries out every year the night before one of her children's special days - and it requires her to stay up late.
That's because once her little ones have gone to bed, Kate sets about making them their very own birthday cake.
And Louis' birthday tomorrow means it's likely to be a late night in the kitchen tonight for the princess as she whips up the birthday treat.
Kate revealed her adorable tradition in 2019 when she and William appeared on a special BBC programme with baking expert Mary Berry called A Berry Royal Christmas.
In it, she spoke of her love for baking and told Mary that when it comes to her children's birthdays: "I love making the cake."
She added: "It's become a bit of a tradition that I stay up 'til midnight with ridiculous amounts of cake mix and icing and I make far too much. But I love it."
But it won't be the only late night Kate will be having in the next week or so - on May 1, just days before the Coronation, she'll up staying up to make a birthday cake for Princess Charlotte, who turns eight the next day.
Both Louis and Charlotte are expected to be at the Coronation of their grandfather King Charles on May 6, while their older brother Prince George has been given a big role - a page of honour to the King.
The 74-year-old King has five grandchildren and he has previously spoken out in the past about how proud and happy he is to be a grandad.
In fact, one of the most adorable moments from the late Queen's Platinum Jubilee celebrations last year saw him allow grandson Louis to climb up onto his knee for a cuddle as they watched the Jubilee Pageant together.
And it appears to Louis as well as his older brother and sister have a special - yet unusual - name for their grandfather.
It has been reported that the trio call him "Grandpa Wales" - a nod to his former title of Prince of Wales, which he held before becoming King.
The name appears to have been inspired by the children's late great-grandmother the Queen, who is said to have referred to her own grandfather King George V as Grandpa England.
