The head of the Church of England is to perform a foot-washing ritual abandoned for hundreds of years.
Dr Williams will be the first archbishop to wash feet in centuries
Archbishop of Canterbury Dr Rowan Williams has announced he plans to wash the feet of the poor on Maundy Thursday.
It will be the first time an Archbishop of Canterbury has performed the act since the Church of England split with the Roman Catholic Church.
BBC religious affairs correspondent Robert Pigott says Dr Williams will discard some of his ceremonial robes - and carry a towel instead.
The ritual commemorates Jesus's washing of his disciples' feet - at that time a very demeaning act - just before his crucifixion.
The Bishop of Salisbury, David Stancliffe, said that in a day of media images, such a symbolic act spoke more powerfully than words.
Dr Williams has marked the start of Holy Week with a trip to Jerusalem to preach at the main Palm Sunday communion service in St George's Cathedral.
He is expected to meet fellow church leaders and representatives of local Christian communities.