At King Charles coronation, Queen Consort Camilla to.wear Queen Mary's Crown

British Queen Consort Camilla will wear Queen Mary's Crown at her and King Charles III's coronation in early May, Buckingham Palace said on Tuesday.

The crown is more than a century old and was commissioned by Queen Mary for her 1911 coronation alongside King George V. It will be modified for the landmark ceremony on May 6.

This is the first time in recent history that an existing crown will be used for the coronation of a consort instead of a new commission being made, according to the palace.

It said the move was being made "in the interests of sustainability and efficiency".

The crown will be reset with several Cullinan diamonds -- cut from what was the largest diamond ever mined when it was discovered in South Africa in 1905 -- in tribute to the late Queen Elizabeth II.

The diamonds were part of her personal jewellery collection for many years and she often wore them as brooches.

Some of the diamonds were set into Queen Mary's Crown for the 1911 coronation and for King George VI's coronation in 1937, when it was worn as a regal circlet.

It has been removed from its usual display at the Tower of London for the modification, which will also include some other minor changes and additions by the crown jeweller.

Four of its eight detachable arches will be removed to create a new impression, different from that of 1911.

King Charles will wear the St Edward's Crown for the coronation service in Westminster Abbey. It has already been modified and returned to public display in the Tower of London.