Queen Elizabeth told the British people on Sunday that they would overcome the coronavirus outbreak if they stayed resolute in the face of lockdown and self-isolation, invoking the spirit of the Second World War in an extremely rare broadcast to the nation.

In what was only the fifth televised address of her 68-year reign outside her usual annual Christmas Day speech, Elizabeth called upon Britons to show the resolve of their forebears and demonstrate they were as strong as generations of the past.

"We will meet again," she pointedly said in a direct reference to the most famous British song from the war years of the 1940s, when she was a teenager. "Better days will return."

"Together we are tackling this disease, and I want to reassure you that if we remain united and resolute, then we will overcome it," the 93-year-old monarch said in the address from her Windsor Castle home where she is staying with her husband Prince Philip, 98.

"While we have faced challenges before, this one is different. This time we join with all nations across the globe in a common endeavor, using the great advances of science and our instinctive compassion to heal. We will succeed — and that success will belong to every one of us."

'I know that Canadians will remain optimistic'

Gov. Gen. Julie Payette shared a statement from the Queen to Canadians after the address.

"As the people of Canada experience profound and rapid changes to their lives, we are all concerned about the future. It may be difficult to remain hopeful when faced with loss and uncertainty, but Canadians have many reasons for optimism, even in the most trying times," the Queen said in the statement.

"I know that Canadians will remain optimistic and will rise to the challenges ahead. My thoughts and prayers are with the people of Canada at this time."

In comments of her own, Payette thanked the Queen for her leadership.

"In these most difficult times, it is absolutely essential to stay the course, to not get discouraged, and to continue to do our part," she said.

"It is important to hold fast to news that gives us hope and to the lifelines that are all around us: the people who have recovered, the stories of mutual aid and solidarity from every part of Canada, the steadfastness of our public officers, the courage and dedication of our health care professionals, our collective resilience."

Isaac, four, watches Queen Elizabeth during a televised address to the nation in London on Sunday. (Simon Dawson/Reuters)

The Queen's broadcast came hours after officials said the death toll in Britain from the virus had risen by 621 in the last 24 hours to 4,934 with high fatalities still expected in the next week.

U.K. Prime Minister Boris Johnson is among those in self-isolation after testing positive for COVID-19, and the queen's own son and heir Prince Charles, 71, has recovered after suffering mild symptoms of the virus.

Johnson was admitted to hospital Sunday night as a precaution, 10 days after his initial diagnosis. His symptoms are persistent, Downing Street said in a statement.

Like many countries in Europe, Britain is in a state of virtual lockdown, with people told to stay at home unless it was essential to go out. Health Minister Matt Hancock said even stricter rules might be imposed if the current rules to curb the spread of the virus were flouted.

Second World War spirit

Elizabeth thanked those who were staying at home, thereby helping to spare others from suffering the grief already felt by some families, but acknowledged self-isolation could be hard.

She also paid tribute to health care staff for their selfless work and commended the "heart-warming" stories of people across the Commonwealth, of which she is head, and beyond for delivering food and medicines to those who needed them.

WATCH | Queen urges unity, strength in special COVID-19 address:

The Queen urged Britons to show unity and strength during the coronavirus pandemic in a special televised speech. 3:35

Sunday's address was an extremely rare one as the queen usually only speaks to the nation in her annual televised Christmas Day message.

In order to ensure any risk to the elderly monarch herself was mitigated, it was filmed in a big room to ensure a safe distance between her and the cameraman, who wore gloves and a mask and was the only other person present.

Elizabeth said the situation reminded her of her first ever broadcast in 1940, when she and her late sister Margaret spoke from Windsor to children who had been evacuated from their homes to escape bombing raids by Nazi German aircraft.

"Today, once again, many will feel a painful sense of separation from their loved ones. But now, as then, we know, deep down, that it is the right thing to do," she said.

In the future people could take pride in how they too had dealt with disruption to their lives, and that the wartime stoicism of the British was not something from the past, but part of the present and future.

"Those who come after us will say the Britons of this generation were as strong as any," she said. "That the attributes of self-discipline, of quiet good-humoured resolve and of fellow-feeling still characterize this country."

She concluded by invoking the words of the song "We'll Meet Again" by Vera Lynn from World War Two which became a symbol of hope for Britons during the conflict.

Read Queen Elizabeth's full remarks:

"I am speaking to you at what I know is an increasingly challenging time. A time of disruption in the life of our country: a disruption that has brought grief to some, financial difficulties to many and enormous changes to the daily lives of us all.

"I want to thank everyone on the NHS [National Health Service] front line, as well as care workers and those carrying out essential roles, who selflessly continue their day-to-day duties outside the home in support of us all. I am sure the nation will join me in assuring you that what you do is appreciated and every hour of your hard work brings us closer to a return to more normal times.

"I also want to thank those of you who are staying at home, thereby helping to protect the vulnerable and sparing many families the pain already felt by those who have lost loved ones. Together, we are tackling this disease, and I want to reassure you that if we remain united and resolute, then we will overcome it.

Peter, Kate Beresford and family members in the garden watch Queen Elizabeth during a televised address to the nation at their home in Manchester, U.K., on April 5. (Phil Noble/Reuters)

"I hope in the years to come everyone will be able to take pride in how they responded to this challenge. And those who come after us will say the Britons of this generation were as strong as any. That the attributes of self-discipline, of quiet good-humoured resolve and of fellow-feeling still characterize this country. The pride in who we are is not a part of our past. It defines our present and our future.

"The moments when the United Kingdom has come together to applaud its care and essential workers will be remembered as an expression of our national spirit; and its symbol will be the rainbows drawn by children.

Jake Weller looks through the window of his house in Aylesbury, Britain, on April 2, underneath a hand-coloured rainbow. Rainbows drawn by children are a symbol of Britain's national spirit during the coronavirus pandemic, according to Queen Elizabeth. (Eddie Keogh/Reuters)

"Across the Commonwealth and around the world, we have seen heart-warming stories of people coming together to help others, be it through delivering food parcels and medicines, checking on neighbours or converting businesses to help the relief effort.

"And though self-isolating may at times be hard, many people of all faiths, and of none, are discovering that it presents an opportunity to slow down, pause and reflect, in prayer or meditation.

"It reminds me of the very first broadcast I made, in 1940, helped by my sister. We, as children, spoke from here at Windsor to children who had been evacuated from their homes and sent away for their own safety. Today, once again, many will feel a painful sense of separation from their loved ones. But now, as then, we know, deep down, that it is the right thing to do. While we have faced challenges before, this one is different. This time we join with all nations across the globe in a common endeavour, using the great advances of science and our instinctive compassion to heal. We will succeed — and that success will belong to every one of us.

Ellie Recine in Newcastle-under-Lyme, Britain, watches Queen Elizabeth during a televised address on April 5 as the spread of the coronavirus disease continues. (Carl Recine/Reuters)

"We should take comfort that while we may have more still to endure, better days will return: we will be with our friends again; we will be with our families again; we will meet again.

"But for now, I send my thanks and warmest good wishes to you all."