Buckingham Palace on Friday announced that a period of mourning for the Royal Family will be observed from now until seven days after the funeral of Queen Elizabeth II.
Queen Elizabeth II, the UK's longest-serving monarch, died on Thursday at Balmoral Castle in Scotland after reigning for 70 years. She was 96.
The date of the Queen's funeral has not yet been confirmed.
In a statement, Buckingham Palace says: 'Following the death of Her Majesty The Queen, it is His Majesty The King's wish that a period of Royal Mourning be observed from now until seven days after The Queen's Funeral.'
Separate to the national mourning, which the government is expected to outline on Friday, Royal mourning is to be observed by 'members of the Royal Family, Royal Household staff and Representatives of the Royal Household on official duties, together with troops committed to Ceremonial Duties'.
The Queen's state funeral is expected to take place at Westminster Abbey in less than two weeks.
The exact day will be confirmed by Buckingham Palace, the BBC reported.
On Friday, there will be a remembrance service at St Paul's Cathedral, attended by the prime minister Liz Truss and other senior ministers.
Because the Queen died in Scotland, her coffin will lie at rest at St Giles' Cathedral in Edinburgh. The public may be allowed to view the coffin after a few days.
The coffin will then be flown to London, where hundreds of thousands of people will be allowed to file past over a period of four days' lying in state at Westminster Hall.
King Charles will hold his first audience with British Prime Minister Truss on Friday after which a joint Parliament session will pay tribute to the Queen. The regular business of government is at a halt, unless anything urgent occurs, with the focus to fall entirely on the Queen during the 10-hour sitting of Parliament.
In central London, 96 rounds of gun salutes -- one for every year of the Queen's life -- will be fired in tribute to the late monarch.
Churches will also toll their bells, with the Church of England sending out guidance to parishes, chapels and cathedrals across the country encouraging them to open for prayer or special services.
Truss and senior ministers will attend a public service of remembrance at St Paul's Cathedral in central London and then the government is due to confirm the length of national mourning, which is likely to be around 12 days, from now up to the day after the Queen's funeral.
The funeral day will be a public holiday in the form of a Day of National Mourning.
King Charles will meet the Earl Marshal, the Duke of Norfolk, who is in charge of the Queen's funeral, to sign off on the pre-set schedule for the coming days under Operation London Bridge.
The 73-year-old King will decide on the length of court or royal mourning for members of the royal family and royal households, which is expected to last a month.
His first televised address to the nation on Friday evening will pay tribute to his mother as he pledges to serve as Head of State.
On Saturday, there will be a special session of the House of Commons for members of Parliament to take an oath of allegiance to King Charles III and end in a 'formal humble address to His Majesty The King'.
Alongside, an Accession Council will meet at St James's Palace in London to formally proclaim Charles as the new sovereign.
The first public proclamation of the new sovereign will then be read in the open air from the Friary Court balcony at St James's Palace by the Garter King of Arms.
Union flags, which are flying at half-mast across the country, go back up to full mast at 1 pm and remain there for 24 hours to coincide with the proclamations before returning to half-mast in mourning.
