King Charles III will lead senior royals on foot, accompanying the Queen’s coffin on its way to Westminster.
He will be joined by Princess Anne, 72, the Duke of York, 62, the Earl of Wessex, 58, and the new Prince of Wales, 40.
Also walking through the procession will be Prince Harry, 37, alongside Princess Anne’s husband, Vice Admiral Sir Tim Laurence and her son, Peter Phillips.
Other Royal Family members will wait for the procession to arrive at Westminster.
The Queens coffin is expected to arrive at Westminster Hall at 3pm.
The Queen Consort joined King Charles on his trip to Northern Ireland earlier this week.
The royal couple arrived in Belfast on Tuesday, viewing tributes laid at Hillsborough Castle.
They had previously travelled to Edinburgh, where Camilla watched on as the King led the Vigil of the Princes around his mother’s coffin at St Giles’ Cathedral.
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The former monarch’s state funeral will take place at Westminster Abbey on September 19 at 11am.
Since her death was announced, thousands of people have travelled to Buckingham Palace, Windsor Castle and Balmoral to pay their respects.
It was initially estimated that 40,000 people would turn up each day to pay their respects.
But Whitehall chiefs in charge of logistics for the five-night vigil have since estimated that more than 750,000 may wish to attend.
Infrastructure has been set up in preparation for miles of queues.
From 9am on Tuesday, private security staff and stewards in hi-vis vests and Metropolitan Police officers will be stationed along the route.