After the passing of Queen Elizabeth II, former Canadian prime ministers are paying their respects and sharing their favourite memories of the monarch.

Jean Chretien, Canada's 20th prime minister, called the late Queen a "fantastic monarch" and said her death was "an enormous loss for all of us."

"She's done it for 70 years with a lot of grace and a lot of competence and she was respectful of everybody and everybody respected her," he told CTV's Power Play on Thursday.

Over the course of her 70-year reign, 12 Canadian prime ministers have served at Her Majesty's pleasure, from Louis St. Laurent to Justin Trudeau. The Queen also visited Canada 31 times, more than any other country.

Chretien recalls one royal visit in 1970, where he took The Queen and Prince Philip to see the Northwest Territories in a small propeller plane back when he served as what was then known as minister of Indian affairs and northern development.

"It was a great occasion of exchanging. You know, she used up the occasion to practice her French, that was excellent. And it was the same thing for Prince Philip and they were … talking about all sorts of issues in the other official language of Canada," Chretien said. "It was an amazing trip."

Chretien also noted The Queen's sense of humour. In 1982, he was justice minister and had gathered with The Queen and then-Prime Minister Pierre Trudeau to sign the repatriation of the constitution. But when it was his turn to sign the document, his fountain pen broke, and Chretien uttered a swear word in French.

"The Queen looked to the left, to the right, and bursts in a big laugh. And everybody was asking me for years what I had said for her to laugh," Chretien explained. "She understood that and she checked to know if anybody had heard me. And it was the story and she had fun out of it."

Brian Mulroney, who served as prime minister from 1984 to 1993, said the late Queen had "impeccably good judgment" and called her "thoughtful, very witty and kind."

For Mulroney, his fondest memory of The Queen was the behind-the-scenes role she played in the Commonwealth to help end South African apartheid.

"Her thoughtful, wise, brilliant leadership -- all private … was indispensable to the success that the Commonwealth enjoyed in our two principal objectives that very difficult time, namely the liberation of Nelson Mandela, and the destruction of the apartheid system," Mulroney told CTV National News on Thursday.

Mulroney oversaw difficult and divisive negotiations for constitutional amendments, as well as the strengthening of the Quebec sovereignty movement. But even during these difficult times, Mulroney said The Queen remained a steadfast friend to Canada.

"She said, 'I am not a fair-weather friend.' And she was not. She was with us all the way," he said. "She loved the country. She loved the people and her conduct spoke very generously of that."

Former minister Stephen Harper said The Queen's death "marks the end of an extraordinary era of service and a great loss for our country."

"In my many personal meetings with Her Majesty, she was always warm, knowledgeable, and engaging, and I shall remember those times with great affection," he said in a statement.

Harper's predecessor, Paul Martin, said in a statement The Queen was "deeply inquisitive and keenly informed" and also noted the monarchy "conjures up a wide range of reactions" given its history of colonialism.

"The complex task of reconciliation continues to challenge Canada and, there is no doubt in my mind that a lifetime of service and duty gave Her Majesty a unique appreciation of the need to address history's failures and make way for change," Martin said.