Kate Middleton

After meeting the bilby, William and Kate unveiled a plaque that read: "A national gift from the Commonwealth Government to commemorate the birth of His Royal Highness Prince George of Cambridge."

Australia's government under former prime minister Kevin Rudd gave Taronga Zoo's bilby preservation programme a £5,500 donation as a national gift to commemorate George's birth on July 22 last year.

The baby prince interrupted the zoo chief executive's speech with some enthusiastic squealing before gleefully taking a present from him, a stuffed toy bilby.

There was another gift, a yellow car sticker that said "Wild child on board," which George happily took and tried to chew. "Munch, munch, munch," said William.

His son threw the toy bilby on the floor, as he tried to chew the sticker, to the laughter of everyone watching. William, who was wearing a blue short-sleeved check shirt and navy trousers, said: "He does love it honestly".

Mr Kerr said he hoped the royal visit would help highlight efforts to conserve Australia's native animals.

He said: "Bilbies were once found right throughout Australia, but are now threatened in the wild.

"Taronga is part of a national breeding programme across a number of Australian zoos and wildlife organisations that are involved in conservation, breeding and research to provide an insurance population to safeguard this species into the future."

Chris Jackson

SYDNEY, AUSTRALIA - APRIL 20: Prince William, Duke of Cambridge holds Prince George of Cambridge they unveil a plaque opening the Bilby enclosure as Catherine, Duchess of Cambridge looks on during a visit to at Taronga Zoo on April 20, 2014 in Sydney, Australia. The Duke and Duchess of Cambridge are on a three-week tour of Australia and New Zealand, the first official trip overseas with their son, Prince George of Cambridge. (Photo by Chris Jackson/Getty Images)