Kate Middleton and Prince William have welcomed a new addition to the family thanks to a generous gift from her brother.

The Duke and Duchess of Cambridge and their three children are "besotted" with the adorable cocker spaniel.

James Middleton, who has bred dogs since 2011, gave the family the eight-month-old black puppy as a gift shortly before their beloved dog Lupo died.

It's believed he had some help from Prince George and Princess Charlotte when it came to deciding on which puppy they should have.

The new puppy, who is Lupo's nephew, is now quite at home at Anmer Hall, the Cambridge's Norfolk residence.

Kate Middleton, Prince William, Prince George and Lupo
Lupo appeared in the first official family photo after Prince George was born

A friend told the Mail on Sunday: "The new puppy is adorable and the whole family are besotted.

"They were devastated when Lupo passed away, as any dog owner will understand, but got the new puppy before he died

"It was hoped that a younger dog would give Lupo some company and give him a little more life and energy."

James bred a litter of puppies from his dog Ella in 2011, and gave Lupo to Kate when Prince William was deployed to the Falklands.

Lupo, who lived with the couple in Anglesey, helped Kate cope with all the time apart she was spending from William in the early years of their marriage.

Prince George and Lupo
Lupo even helped pick Prince George's name
The eight-month-old black puppy (pictured in the arms of Alizee Thevenet) was a gift from the Duchess’s brother James Middleton

Lupo's sister Luna bred a littler of six puppies last summer while James and his fiancee Alizee Thevenet stayed with his parents in Berkshire.

The engaged couple shared a photo of themselves with the adorable litter on Instagram.

Prince George, seven, and Princess Charlotte, five, are understood to have had the pick of the litter before deciding on the new puppy.

William and Kate were left devastated by Lupo's death and shared a rare personal message on their social media when he died in November.

The couple said Lupo had been 'at the heart' of their family.

William and Kate 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"

Lupo was even responsible for picking Prince George's name in a game organised by the royals.

The cocker spaniel also appeared in the first official family photo after Prince George was born.