The siblings, who are second and third in line to the throne, will be followed by Prince Harry and Meghan Markle.
King Charles and Camilla, the Queen Consort will lead the procession into the Abbey.
The new details come just hours after King Charles issued a statement of thanks after 10 days of public mourning for the Queen.
"Over the last ten days, my wife and I have been so deeply touched by the many messages of condolence and support we have received from this country and across the world," he said.
"In London, Edinburgh, Hillsborough and Cardiff we were moved beyond measure by everyone who took the trouble to come and pay their respects to the lifelong service of my dear mother, the late Queen."
Over the weekend, Queen Elizabeth's four children, King Charles, Princess Anne, Prince Andrew and Prince Edward gathered at Westminster Hall for a vigil around her coffin.
Four of the late monarch's great-grandchildren, Savannah Phillips, Isla Phillips, Mia Tindall, and Lena Tindall, also attended the vigil alongside their parents.
Following today's funeral service, which will start at 8pm AEST, a gun carriage procession will take the Queen's coffin past Buckingham Palace and arrive at Hyde Park Corner at 1 pm.
The coffin will be moved to a hearse and move towards Windsor Castle, where a committal service will be held at 4 pm at St George's chapel.
Following the service, the coffin will be lowered into the Royal Vault.
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This story originally appeared on our sister site, Now To Love.