Prince William and his wife Kate have released two informal family snapshots as the first official photos of their son, Prince George.

George, the third in line to the British throne, was born on July 22 amid a global media frenzy, reflecting the international popularity of his parents and ongoing fascination with the royal family.

The Duke and Duchess of Cambridge gave the world the first glimpse of their newborn son when they left a London hospital the day after his birth but he has not been seen since.

However, instead of a traditional formal photograph for George's first official photo shoot, the couple released two shots taken by the duchess's father, Michael Middleton, in early August in the garden of her family home in Berkshire.

One photo shows Prince William, in a blue, open-necked shirt and jeans, with his arm around Kate, dressed in a fuchsia-coloured dress and holding their sleeping son wrapped in a crocheted, white blanket.

The second photo shows the couple sitting on a picnic blanket with Kate again holding a sleeping Prince George. With them is their beloved black cocker spaniel, Lupo, while the Middleton family's golden retriever, Tilly, lolls at one side.

The photos are a far cry from the formal photographs released of Prince William a month after his birth in 1982 in which he was alert and wearing a long, laced gown. The pictures with his mother, the late Princess Diana, and father Prince Charles were taken by his great-uncle, photographer Lord Snowden.

Some royal watchers were disappointed that the first photos released of Prince George failed to show his face and were not of a professional quality.

But the decision to eschew tradition for a more informal approach was seen as true to form for William and Kate, both 31, who have tried to break away from royal traditions of rigid formality, be it by changing nappies themselves or William driving his family away from the hospital.

The photos were released a day after Prince William gave his first interview since the birth, describing his son as a "little bit of a rascal" who does not want to go to sleep.

"As a few fathers might know I'm actually quite looking forward to going back to work," joked William, who is second in line to the throne after his father.