Queues are already starting to form in London ahead of the Queen's arrival to Westminster Hall in the Houses of Parliament, where she will be lying-in-state for four days.
This will begin at 17:00 BST on Wednesday and will last until 06:30 on Monday 19 September - the day of the Queen's funeral.
The queue begins at Lambeth Bridge, where mourners are preparing for a long wait.
Grace and Vanessa have been waiting in line overnight to pay their respects.
Grace says she has "always followed royal events" after her father who, as part of the Irish Guards, was involved in the Queen's coronation.
"This morning, we went to the actual rehearsal of Her Majesty's coffin going into Westminster Hall. It was heartbreaking, the solemness of the occasion," she tells BBC Breakfast.
"I think the whole nation is going to be heartbroken and in floods of tears - we were."
Vanessa says it is a "unique, once-in-a-lifetime" occasion.
"This is the way we want to pay respect to the Queen who has done a great service to the country and the Commonwealth and the world," she adds.