King Charles III speaks at St James's Palace, London, on Saturday. AP
The new monarch will also join senior royals for a vigil at St Giles' Cathedral where the coffin will lie at rest before being flown to London on Tuesday.
Since Elizabeth's death aged 96 at Balmoral Castle, her Scottish holiday home, a choreographed series of plans to mourn Britain's monarch of 70 years has been put into operation.
On Sunday, her oak coffin, draped in the Royal Standard of Scotland with a wreath on top, was taken by hearse on a six-hour journey from Balmoral through picturesque Scottish countryside, villages, small towns and cities to Edinburgh.
Tens of thousands of well-wishers lined the roads to pay their respects, while huge crowds, some in tears, gathered in Edinburgh to greet the cortege.
People line the streets as the hearse carrying the coffin of Queen Elizabeth II passes through in Scotland. AP
"I think when the queen's coffin emerged from Balmoral Castle yesterday, I think that it was a moment of enormous significance," John Swinney, Scotland's Deputy First Minister told BBC radio.
"And I think people drew breath, because what we've all been living through over the last few days suddenly became real, it became visible."
Before setting off for Scotland, Charles, 73, who automatically became king of the United Kingdom and 14 other realms including Australia, Canada, Jamaica, New Zealand and Papua New Guinea, will travel to the British parliament for another traditional ceremony.
At Westminster Hall, lawmakers from both the House of Commons and the upper House of Lords will express their condolences for the death of his mother, and the king will deliver a response.
He will then fly to Edinburgh with his wife Camilla, the Queen Consort, to join his sister Anne and brothers Andrew and Edward.
The queen's children will walk behind the hearse as the coffin of their mother is taken to St Giles' Cathedral, flanked by soldiers.