The Queen, who usually only records speeches for broadcast on Christmas Day, thanked health workers and urged people to take comfort in the fact that 'better days' were coming.
The Queen said, '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.
'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.'
The recording was made with just one cameraman present, wearing gloves and a mask, present at Windsor Castle where the monarch is isolating.
Although addressed to the United Kingdom and the Commonwealth, the speech was broadcast around the world.
In it, the Queen also paid tribute to those performing acts of helpfulness and kindness during the pandemic.
'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, ' she said.
'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.
The monarch also expressed her gratitude to health workers.
She said, 'I want to thank everyone on the NHS 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.'
It is only the fifth time the Queen has addressed the UK and Commonwealth via a television broadcast outside of her traditional Christmas message.
The previous speeches came at the start of the Gulf War in 1991, at the death of Diana, Princess of Wales in 1997, ahead of the funeral of Queen Elizabeth the Queen Mother in 2002 and to mark her Diamond Jubilee in 2012.