The government announced the silence - officially called a National Moment of Reflection - on Monday, as the country mourns the death of Elizabeth II.
The Queen, who was 96, died at Balmoral Castle in Scotland on Thursday, September 8.
Announcing the 'moment of reflection', the government invited people to mark it in whichever way they see fit.
"The silence can be marked privately at home, with friends and family, out on doorsteps or the street with neighbours, or at locally arranged community events and vigils," the government said.
"Community groups, clubs and other organisations across the country are encouraged to take part."
Downing Street said the “shared national moment of reflection” will be an opportunity for everyone across the UK to mark the Queen’s death, with the Prime Minister's official spokesman adding that people are encouraged to “come together”.
What time is the one-minute silence?
The silence will be held at 8pm tonight.
The PM's official spokesman said: "At 8pm on Sunday September 18, the night before the state funeral, there will be a one-minute silence where the public are invited to come together and observe a national moment of reflection to mourn and reflect on the life and legacy of Queen Elizabeth II."
Those living overseas are encouraged to take part at 8pm their time.
The spokesman also suggested commuters may want to “change their working patterns accordingly” as the capital will be “extremely busy” for the Queen’s lying in state.
The Queen's state funeral will take place at 11am on Monday at Westminster Abbey, before Her late Majesty is buried at St George's Chapel, Windsor Castle.