OTTAWA -- Former astronaut Julie Payette will be Canada's next Governor General, becoming the fourth female to be the monarch's representative in Canada when she is sworn in later this year.

Payette's appointment was formally announced Thursday by Prime Minister Justin Trudeau, and the 53-year-old from Montreal was emotional as she reflected on what's ahead.

"This is a very great honour for me and for my family, for my friends and my colleagues here around the country, on the planet and even a few outside the planet," she said from the Senate foyer minutes after her appointment was announced.

She will be taking over from Gov. Gen. David Johnston, whose term expires in September.

"Ms. Payette's life has been one dedicated to discovery, to dreaming big and to always staying focused on the things that matter most," Trudeau said.

"These truly Canadian traits, along with her years of public service, make her unquestionably qualified for this high office."

Payette was the first Canadian female to board the International Space Station in 1999. She went on a second space flight in 2009.

She is fluently bilingual, and she also learned Russian after being named an astronaut.

She has corporate and board experience through her time at the Canadian Space Agency and as a vice-president at the Canada Lands Co., which oversees the sales of unneeded federal properties.

And she has military experience: Payette qualified as a military jet captain in 1996 after logging hundreds of hours of flight time on the CT-114 Tutor jets, the same ones flown by the Snowbird team.

The Governor General is the military's commander-in-chief, but acts on the advice of the government.

Payette's selection caps a remarkable story.

As a girl growing up in Montreal, she dreamed of going into space but never thought it was possible because she was female, Canadian and didn't speak a word of English.

Instead, her family encouraged her interests and on her first space flight she helped assemble the International Space Station, which fellow Canadian Chris Hadfield would later command.

She will be installed as Governor General during a ceremony this fall.

But first, she will go through weeks of briefings and preparations to take over from Johnston, as well as have a meeting with the Queen.

"The task will be hard because it requires to follow in the footsteps of giants," Payette said of the man she is replacing.

Johnston is expected to have an audience with the Queen next week when he travels to the U.K. for Canada 150 events, likely marking the last time he will sit face-to-face with the monarch he represents.

"I am certain that she will fulfil this role with intelligence, grace and energy, and that she will bring qualities of curiosity, courage and compassion to her mandate," he said in a statement from Beijing, where he is currently on an official visit.

Johnston agreed to extend his tenure at Rideau Hall by two years ending this fall so that an experienced viceregal could navigate any parliamentary and constitutional dilemmas that could have arisen had the 2015 federal election ended with a minority government.

During his tenure as Governor General, Johnston focused on education, philanthropy and innovation, and also making awards like the Order of Canada more accessible to Canadians.

Payette said she was still thinking about how she'll handle the role.

"You can imagine though that it might be related, some of it, to science, technology and moving forward in a society of knowledge," she said.