The late monarch’s coffin will remain in Westminster Hall for the public to view until 6.30am on Monday, ahead of the state funeral in Westminster Abbey.
It means Sunday is likely to be the last chance to join the queue.
At 8pm, the country will observe a one-minute silence to remember the Queen, with people invited to mark the occasion privately at home, on their doorstep or street, or at community events and vigils.
It will come shortly after Queen Consort Camilla pays a televised tribute to the late monarch, recalling her “wonderful blue eyes” and saying: “I will always remember her smile.”
In pre-recorded words on the BBC, she will speak of how Queen Elizabeth II was a “solitary woman” in a male-dominated world.
She will add: “I can’t remember anyone except the Queen being there.”
There will also be a service of reflection near Falkirk, Scotland at 7.30pm.
It will see 96 lanterns, one for each year of the late monarch’s life, lowered into the pool of reflection at the foot of the Queen Elizabeth II Canal, before wreaths are placed into the water.
It comes as world leaders travel to the UK ahead of Monday’s funeral service.
The DCMS has said the historic occasion will be shown on giant screens in various locations across the UK – from London’s Hyde Park to Coleraine Town Hall in Northern Ireland.
Around 125 cinemas will also be screening the event – and it will be aired live on GB News.
On Saturday evening, Queen Elizabeth II's eight grandchildren together staged an evening vigil around the late monarch's coffin.
Prince William, at the head of the coffin, with his brother Prince Harry at the foot, both in the Blues and Royals No 1 uniform, stood with their heads bowed in her honour in Westminster Hall.
William was flanked at the corners by his cousins Zara Tindall and Peter Philips.
While Harry was between Princesses Beatrice and Eugenie, with 18-year-old Lady Louise Windsor and James, Viscount Severn at the middle on either side of the coffin.
The grandchildren, invited by the King, had wanted to pay their respects as their parents had done the evening before.
William and the King also went on a walkabout in the afternoon to greet mourners in the queue for the Lying-In-State, after Charles was given a tour of the Metropolitan Police Service Special Operations Room.
Queen Elizabeth II's coffin in Westminster Hall
POOL
Mourners have queued up for hours to see Queen Elizabeth II Lying-In-State
Paul Ellis