The Duke and Duchess of Cambridge begin their tour of Canada today accompanied by their two young children.
William and Kate will introduce Prince George, aged three, and 16-month-old Princess Charlotte to the Commonwealth country during the eight-day visit.
Highlights of the trip to Canada's east coast will see William and Kate experience the stunning natural world of the province of British Columbia and the territory of Yukon, where they will go fishing, mountain biking, sightseeing and meet First Nations communities.
As a contrast they will also learn how the country is dealing with social problems like mental health issues, the refugee fallout from the Syrian conflict and drug and alcohol addiction among mothers, during visits to organisations and projects.
The tour of Canada will be Charlotte's first official royal visit, but George travelled to Australia and New Zealand with his parents in 2014 when he was nine months old.
He stole the limelight from his mother and father whenever he made an appearance - joining a playgroup in the New Zealand capital Wellington and enjoying a family trip to the zoo in Sydney.
As the Commonwealth country is one of the Queen's 16 realms - nations where the monarch is head of state - the visit will be a homecoming for the Cambridges.
The country's Globe And Mail newspaper has described the trip as a "match made in paparazzi heaven, featuring Prince William, Prime Minister Justin Trudeau and their equally telegenic families''.
Canada's prime minister invited the Cambridges to visit in July and the politician and wife Sophie Gregoire Trudeau who have three children - eight-year-old Xavier, seven-year-old Ella-Grace and two-year-old Hadrien - are expected to join the royal couple for a number of events.
The royal couple and their children will arrive late this evening, UK time, in a Royal Canadian Air Force jet which will touch down in Victoria, the capital of British Columbia.
William and Kate will travel with a 12-strong entourage - three private secretaries, a communications team of four, tour secretary, operations manager, personal assistant, and - paid for privately - a hairdresser and nanny.
They will receive an official welcome at the British Columbia Parliament Buildings in Victoria after their arrival and later meet with senior Canadian leaders at Government House where they will be based for their visit.
Tomorrow the royal couple will travel to nearby Vancouver by sea plane where they will carry out a day of engagements.
They will visit the Immigration Services Society of British Columbia where they will meet some of the thousands of Syrian refuges who have arrived from UNHCR camps and at a separate event learn about an outreach programme providing health and social services support to pregnant women and mothers with drug and alcohol issues.
A Kensington Palace spokesman said: ''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 2,000 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.''