A final star-studded performance chronicling the events of the Queen's life will be held on Sunday in the grounds of Windsor Castle.
The show will celebrate the Queen's love of horses, her dedication to the Commonwealth and international affairs and her deep involvement with the Navy, Army and Air Force.
There will be 900 horses and more than 1,500 people taking part to chronicle the Queen's birth, through to World War Two, her marriage, the Coronation and a reign of more than 60 years.
ITV News caught up with a number of the stars during rehearsals.
- Katherine Jenkins
The Welsh classical and pop singer will be performing at a key moment in the show: the point of the Queen's Coronation.
- Alan Titchmarsh
The TV gardener will be part of the narrating and compering team.
- James Blunt
James Blunt, who left the army in 2002, will be singing during the performance - backed up by some of his old military colleagues.
- Imelda Staunton and Jim Carter
Husband and wife actors from Downton Abbey will be giving a rare stage performance together.
You can watch live coverage of the star-studded event, hosted by Ant & Dec, on ITV from 8.35pm on Sunday.