Prince William and Kate steal the show on Canada Day

(CBS/AP) Updated 2:18 p.m. EDT

OTTAWA, Ontario - Prince William and Kate joined in Canada Day celebrations on Friday, during the second day of their first official overseas trip.

The Duke and Duchess of Cambridge, as the couple is formally known, often stole the show as they were feted by Canadian leaders and cheered by tens of thousands who lined the streets of the Canadian capital to get a glimpse of them.

Pictures: William and Kate celebrate Canada Day
Pictures: William and Kate kick off Canada tour
Pictures: Kate's royal looks

Canadian Prime Minister Stephen Harper welcomed them to an afternoon program at Parliament Hill as "the world's most famous newlyweds" and said they represent "our unbreakable link with our past and our unqualified optimism for the future."

The crowd - many dressed in Canada's red and white colors - exploded in prolonged cheering and chants of "Will and Kate, Will and Kate." A few wore homemade crowns in a nod to the royals.

In his speech marking Canada's 144th birthday, the prince talked of his and Kate's family ties to Canada - in French and English, as he had a day earlier.

He said that Kate had learned about Canada from her late grandfather, "who held this country dear to his heart for he trained in Alberta as a young pilot during the Second World War."

On his side, he spoke of his grandmother, Queen Elizabeth II. The queen, he said, "has asked me to convey her warmest good wishes to the people of Canada, and her happy and abiding memories of being on Parliament Hill with the Duke of Edinburgh one year ago."

The prince referred to his grandmother as "the Queen of Canada," since she remains Canada's head of state, drawing a loud cheer from the crowd. He added that the queen was watching their Canada tour with interest.

Kate was resplendent in Canadian colors, a cream dress by the London designer Reiss (the same dress she wore for the couple's official engagement portrait last year), complete with the Queen's maple leaf brooch, and a brilliant red hat topped with a maple leaf. Queen Elizabeth loaned the brooch to the duchess for the tour; it was first worn in 1951 by the then-Princess Elizabeth on her first visit to Canada.

Prince William wore an understated blue suit and a red tie.

Police estimated that some 300,000 people were gathered around Parliament Hill to watch the Canada Day show. A 21-gun salute to Canada's and military plane flyovers were part of the pageantry.

When two F-18's did a flyby, Kate mouthed "that scared me" and put her hand to her heart.

The Duke and Duchess of Cambridge began their day by handing out flags to newly minted Canadians at a citizenship ceremony.

The couple emerged from their motorcade Friday at the Canadian Museum of Civilization to raucous cheering from hundreds of spectators. The pro-royal spectators drowned out a handful of protesters who oppose requiring Canadian citizens to pledge allegiance to the Queen when they broke into spontaneous renditions of "O Canada" and "God Save the Queen".

The couple watched as 25 people from 14 countries became Canadian citizens. They then handed out red and white maple leaf flags to the newly minted Canadians, then participated in a reception for the new citizens and their families.

William and Kate also released a message to Canadian forces, posted on their royal office's website.

"It is with a deep sense of pride and admiration that we send our best wishes to all members of the Canadian Forces, whether based here at home in Canada or on active service in various parts of the world," they wrote. "We join with all Canadians gathered here on Parliament Hill in thanking you for your extraordinary commitment and contribution to the cause of peace...Godspeed your safe return to your family, your friends and to Canada."

The Duke and Duchess of Camrbidge began their tour on Thursday, laying a wreath at Canada's National War Memorial as excited onlookers screamed with delight and showered the young royals with flowers and gifts. Later, they attended a reception for young Canadians. It was billed as a celebration barbecue but it was brought inside due to rain.

The duke and duchess changed into more casual clothing for the event. William wore an open-necked blue shirt and khakis, while Kate wore a black and white dress wrap dress by Issa decorated with a pattern of birds - the same dress she wore upon arriving to London's Goring Hotel the night on the eve of her wedding day - paired with wedge sandals.

Their nine-day tour will end on July 8, after which the couple will travel on to the United States for a brief stay in the Los Angeles area.