The Duchess of Kent's coffin will be transported from Kensington Palace to Westminster Cathedral on Monday, the eve of her funeral.
A military piper from The Royal Dragoon Guards will lead the procession, with regiment personnel acting as the bearer party.
A requiem mass, a Catholic funeral service, is scheduled for Tuesday and will be attended by the King, Queen, and other senior royals.
This event will be the first Catholic funeral service for a member of the royal family in modern British history.
Duchess Katharine, who passed away peacefully on 4 September aged 92, was the first royal family member in over 300 years to convert to Catholicism in 1994.