The Queen will mark Maundy Thursday by distributing commemorative coins to 90 men and 90 women - each representing one of her 90 years.
The monarch, who is preparing to celebrate her 90th birthday, will be joined by the Duke of Edinburgh for the Royal Maundy service, which is being held in St George's Chapel at Windsor Castle for the first time since 1959.
The 180 recipients of the Maundy money are retired pensioners who have been recommended in recognition of their service to the Church and community. They are traditionally selected from a single diocese but this year have been chosen from across the country.
Pamela Geoghegan, 73, who has taken two trucks and sixteen car-loads of aid to refugee camps in France, and Tim O'Donovan, 84, who authors the annual survey of Royal Family engagements published in The Times since 1979, will be among the recipients.
The Queen will hand two purses - one white and one red - to each person during the service.
The red purse will contain a £5 coin commemorating the Queen's 90th birthday and a 50p coin commemorating the 950th anniversary of the Battle of Hastings, while the white purse will contain uniquely minted Maundy coins, equating in pence to her age.
The Royal Maundy is an ancient ceremony which originated in the commandment Christ gave after washing the feet of his disciples the day before Good Friday.
It appears to have been custom for members of the Royal Family to take part in the service since the 13th century, the Royal Mint said.