Ahead of their anniversary on Thursday, the Duke and Duchess of Cambridge released a beautiful snap together, where Prince William looked lovingly at his wife.
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However, the picture contained a small detail that many people may have missed at a first glance.
The Duke's watch showed that the picture was taken at 11:39am, the perfect time for the royal couple's photoshoot as they could enjoy it and be more relaxed as their children would have been in school or nursery.
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Prince Louis has recently followed in his sister Princess Charlotte's footsteps as he began attending the Willcocks Nursery School in London.
However, the young tot actually began nursery later than his older siblings. Louis joined after he turned three, while Prince George and Princess Charlotte first attended when they were two-and-a-half.
Although the full reason for why Louis began his attendance later than his siblings is unknown, it's likely due to the coronavirus restrictions that had been in place following the third lockdown.
The Duke's watch showed the snap was taken at 11:39am
The family lived at their Anmer Hall residence in Norfolk for much of the lockdown, rather than their London home of Kensington Palace which is near to Willcocks nursery.
So, instead of starting in January at the age of two-and-a-half like his older siblings, he began nursery at the start of Willcocks' summer term.
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Prince George started nursery when he was two-years and five-months-old, attending the Westacre Montessori School in Norfolk.
Meanwhile, Princess Charlotte started Willcocks Nursery School at the age of two-years and eight-months, following the family's move to Apartment 1A at Kensington Palace in London.
Willcocks is a short drive from the Cambridges' family home in Kensington. It operates from a hall of Holy Trinity Church, next door to the Royal Albert Hall and Kensington Gardens, and down the road from the Natural History Museum, Science Museum and Victoria and Albert museum, so Louis can expect various educational outings and visits to the park.
It's likely that Louis will join George and Charlotte at Thomas's Battersea School in September 2022 at the age of four.
The royal couple have three children
On their special day last year, Kate was actually working, joining a roundtable discussion via video link with charities that support new mothers and pregnant women.
In the case of their fourth anniversary, the Duchess was overdue with the couple's second child, Princess Charlotte.
For their first anniversary in 2012, William and Kate spent the weekend in Suffolk, where they attended the wedding of the Duchess' school friend, Hannah Gillingham, the day before.
Kate cooked her husband fish en papillote – fish wrapped in parchment paper – as a nod to the traditional first wedding anniversary gift of paper.
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