Prince George and Princess Charlotte are set to take Canada by storm as they join their parents on a week-long tour of the country this month.
Details of the much-anticipated trip were released by Kensington Palace today - and it is hoped that the two young royals may make as many as four public appearances.
The family will fly into Victoria, on the west coat of Canada, on September 24 on a private jet funded by Canadian taxpayers.
George and Charlotte are expected - jet-lag permitting - to make an appearance together on the steps of the plane as the Duke and Duchess of Cambridge disembark.
William and Kate have decided to base themselves in the city for the duration of the week-long official tour on behalf of the Queen and the British Government. Their home will be Government House, the official residence of the Queen's representative in British Columbia.
The children will be cared for by their nanny, Maria Borrallo, as their parents travel around the region on official engagements.
The cost of bringing Borrallo will be met by the couple "privately", Kensington Palace said.
Prince George undertook his first official Royal tour at the age of 9 months when he travelled with his parents to Australia and New Zealand.
Such was his popularity that the local press dubbed him "the Republican slayer". His 16-month-old sister is likely to be equally popular.
It is understood that the children will undertake at least one official public engagement, when they attend a children's party for military families at Government House on September 29.
It will be Charlotte's first official engagement as a member of the royal family, outside of balcony appearances. But it is hoped that if they are not feeling too jet-lagged the children may undertake another public engagement together in Victoria.
They are also likely to be seen boarding the aircraft when their parents leave the country on October 1.
A spokesman for the couple said: "They have received so many wonderful messages from Canadians since the birth of their children and look forward to having the chance to introduce their young to the country before things like school get in the way."
He added: "The Duke and Duchess consider it an honour to be visiting Canada - the largest Commonwealth Realm - in the year of The Queen's 90th birthday.
"British Columbia and Yukon are among the most beautiful places in the world and home to many indigenous communities.
"The tour will see them take in everything from the bustling global city of Vancouver - population 2.5 million - to the remote and beautiful Bella Bella, home to less than 2000 people.
"Along the way they will meet as many Canadians as possible, and will help celebrate Canada's First Nations communities, its arts and culture, pristine and beautiful environment, and its compassionate and innovative charitable sector.
"This will be a busy tour, with more than 30 engagements over the week, and the Duke and Duchess hope to meet thousands of new people along the way.
"This is a great opportunity to introduce their children to a major realm before school. They enjoyed taking Prince George to Australia and New Zealand and having this opportunity to introduce their children to Canada."
The visit, he said, would be a chance for William and Kate to "deepen their relationship with a country that they will visit many times over the course of their lives".
He added: "They want to help the people of British Columbia and Yukon to celebrate what makes Canada great and to showcase some amazing places to the rest of the world."
The trip has been described as being - unusually for a royal tour - as very "outdoorsy and casual".
There will be very little chance for grand jewels or tiaras, a spokesman joked.
It will include traditional events such meetings with politicians and opportunities to pay their respects to the military.
But there will also be fun aspects - including their arrival in Vancouver on a traditional sea plane and perhaps even some mountain biking.
The couple will also travel to the Great Bear Rainforest, said to be one of the most beautiful places on earth, where they will transfer to a float plane where they will be given an aerial tour of the landscape.
They will then land on the water at Bella Bella's main jetty where they will be ceremoniously welcomed by the Heiltsuk First Nations community.
William and Kate will also get a chance to meet the famous Canadian Rangers in Whitehorse, Yukon, and visit the beautiful Montana Mountain where they may attempt some mountain biking.
Before they leave there will also be time to visit Haida Gwaii, the archipelago on the northern coast of British Columbia that is home to the Haida Nation.
"It is a remote, but very special place," their spokesman said.
When the couple arrive at Skidegate, they will transfer to a traditional Haida canoe and will help to paddle around to the beach at the Haida Heritage Centre and Museum, where they will be officially welcomed.
Inside the centre they will be addressed by the President of the Haida Nation and see a cultural performance from around 30 local children.
They are even set to try their hand at some world-class fishing on the beautiful waters of the Hectate Strate.
Their spokesman added: "The Duke and Duchess are delighted with the programme that has been put together for this tour. They cannot wait to get to Canada and start learning about new parts of a country that will play such an important part of their lives for many years to come."
The couple will travel with an entourage of 12, plus a team of Scotland Yard security guards.
This includes three private secretaries, four press officers, one tour secretary, one operations manager, one PA plus their nanny and Kate's hairdresser, Amanda Cook-Tucker, both of whom are being paid for privately and not by taxpayers.