They wrote: “Very sadly last weekend our dear dog, Lupo, passed away.
“He has been at the heart of our family for the past nine years and we will miss him so much. – W & C.”
The English Cocker Spaniel was bred from a dog owned the Duchess’ parents Michael and Carole Middleton and became part of the royal household in 2011.
Kate is thought to have named Lupo after her paternal great-grandmother, who was born Olive Christiana Lupton.
The unique name also translates to “wolf” in Italian.
Over the years Lupo became a star in his own right and featured in a number of precious photographs of the royals.
The family pet appeared in some of the first official portraits of Prince George – including an outdoor snap sitting next to William as Kate cradles their firstborn in 2013.
Lupo also made an appearance alongside George three years later in 2016.
The pair could be seen on a picnic blanket as George leans in to feed his precious friend.
In his first official interview after becoming a father, William gave Lupo a special mention.
He insisted their four-legged friend had adapted well to another person living in the house.
William said: “For me, Catherine, and now little George, are my priorities. And Lupo.
“He’s coping all right, actually.
“As a lot of people know who have got dogs and are bringing newborn back, they take a little bit of time to adapt, but no, he’s been all right so far.”
The royal dog is also thought to have played a key role in choosing the name of their first child.
Kate and William are understood to have scattered pieces of paper with various names on the floor of their home, and Lupo reportedly stopped when he reached “George”.
In 2013, Lupo hit the headlines in his own right after he got his head stuck in a gate at their home in Bucklebury Manor.
Firefighters rushed to the royals’ home in Berkshire only to find he had managed to release himself before they had arrived.
At the time a Royal Berkshire Fire and Rescue Service spokesman said: “Our crew got to the manor but were told as they arrived at the gates that the dog, which had got its head stuck, had been freed just a few moments earlier so their services were not needed.”
Tributes have poured in on social media following the death of Lupo, including from Kate’s brother James Middleton.
In a touching post on Instagram, he wrote: “It is with great sadness that Lupo, the beloved dog of my sister Catherine and her family has passed away. Lupo was the son of Ella, brother to Zulu, Inka & Luna. He was 9 years old.
“Nothing can ever prepare you for the loss of a dog. For those who have never had a dog, it might be hard to understand the loss.
“However for those who have loved a dog know the truth: a dog is not just a pet; it is a member of the family, a best friend, a loyal companion, a teacher and a therapist.”
Source: EXPRESS CO UK