William and Kate, she in a blue shift dress and he in a blue suit and red tie, were pictured on the runway boarding the Royal Canadian Air Force aircraft at London's Heathrow Airport.
The Duke and Duchess of Cambridge, as they are formally known, are expected to land at 2:00 p.m. local time in Ottawa, the first stop in their whirlwind visit to seven Canadian cities before they head to the U.S.
Upon their arrival, the royal newlyweds will participate in a brief ceremony featuring a piece of music created just for them by the Pipe Major, or director of bagpipe music. The piece is called "St. Andrews Courtship," a nod to the university in Scotland where the couple met and fell in love.
Also designed especially for the royal couple in honor of their first trip to North America together is a personal flag for Prince William.
The flag, unveiled by Canada's prime minister and approved by both the Queen and William, is the first to be created by Canada for a member of the royal family since 1962, when the queen adopted a personal flag for her own use in Canada.
William's flag features three maple leaves, from Canada's national tree. It will adorn the cockpit of the jet carrying the royal couple when they touch down on Thursday afternoon, and will fly from their cars and all buildings they visit or stay in during their trip.
The Royal Itinerary
The North American agenda for the newlyweds, married just this April in a lavish royal wedding, shows the young couple has already mastered one ingredient to a long, happy marriage: compromise.
In Canada, for example, William and Kate, both 29, will visit Prince Edward Island, the location featured in Middleton's favorite childhood book, "Anne of Green Gables." William will have a chance to show his skills as a helicopter rescue pilot by taking part in a water landing demonstration.
And while in Los Angeles, the couple made sure to include a charity polo match, for him, and a tour of an inner-city arts program, for her.
Upon arrival today in Ottawa, the couple will head directly to Canada's National War Memorial for a wreath-laying ceremony.
Then they will travel to Rideau Hall, the official residence of Canada's governor general, David Johnston, where they will be welcomed by Prime Minister Stephen Harper with full military honors, including a 21-gun salute.
Prince William will speak at the official welcome ceremony at Rideau Hall, where crowds are already said to be gathering, before departing for a barbecue to mark the achievements of young Canadians.
Crowds on the Ottawa leg of the couple's tour alone are expected to exceed half a million, a sign of the country's excitement over the duke and duchess' arrival.
It's Middleton's first visit to Canada; William has traveled there before. The trip will be closely followed by the media, with nearly 1,400 journalists accredited to cover the visit.
Canada is a member of the Commonwealth and Queen Elizabeth II, William's grandmother, is its head of state.
"Canada is very much part of her family's story," a royal source told People magazine.