Royals and faith leaders will gather for a moment of history when the first woman to take the role of top bishop in the Church of England is enthroned.
A service before around 2,000 people on Wednesday will mark the symbolic start to Dame Sarah Mullally's ministry as Archbishop of Canterbury.
The Prince and Princess of Wales are set to join those gathered in Canterbury Cathedral to see the 106th Archbishop of Canterbury - and first female to hold the high office in its 1,400-year history - officially installed.
The ceremony will celebrate women, Dame Sarah has said, as she outlined how her historic appointment shows "it's entirely possible for you to follow your dreams and what you want to do".
While the King is technically head of the Church, Dame Sarah has become the most senior bishop and the spiritual leader of the Church and the worldwide Anglican Communion.
Charles will be represented at the ceremony by his son and heir William, alongside his wife Catherine.
Dame Sarah, who was named in the role last October, was congratulated at that time by the King on assuming a position "which is of such importance in the UK and across the global Anglican Communion".
While she was confirmed in post at a St Paul's Cathedral ceremony in January, Wednesday will be the first occasion on which she delivers a sermon as Archbishop of Canterbury.
In an interview with the BBC ahead of the ceremony, she noted the "significance of being the first female archbishop", and paid tribute to "the women that have supported me in my ministry, and also the men as well".
She previously pledged to speak out on misogyny - something she said she had experienced herself and which she insisted must be spoken about "so that you bring it out into the open".
Dame Sarah has replaced Justin Welby in the role, after he announced his resignation in November 2024 over failures in handling an abuse scandal.
She has also previously acknowledged the challenges ahead because of the "legacy of deep harm and mistrust" she said existed after past safeguarding failures in the Church.
In her first presidential address at the Church's Synod - also know as its parliament - in February, Dame Sarah described safeguarding as a "fundamental, non-negotiable responsibility, sharpened by our past failings and shaped by the work we still have to do".
In her BBC interview this week, she said the Church was "seeking to become more trauma informed, listening to survivors and victims of abuse", and she added that "light should be shone on all our actions, and the more senior we are, the more light should be shone".
She reaffirmed her "commitment to do all I can to ensure that the Church becomes safer and also responds well to victims and survivors of abuse".
Wednesday's ceremony is scheduled to go ahead without any specific safety mitigations being required amid the meningitis outbreak in Kent.
Dame Sarah, in a statement issued last week, said her thoughts and prayers were with the families of two young people who have died in the outbreak, saying her "heart goes out to them in their devastating loss".
The service will not involve Holy Communion, but those gathered may exchange handshakes as is traditional in offering a sign of peace to those nearby.
The ceremony is taking place despite a recent meningitis outbreak in Canterbury, which sparked a vaccination rollout to students in the area (Gareth Fuller/PA)
Officials have said they are keeping in contact with health authorities to monitor the situation, but that the event "remains categorised as low risk so will proceed as planned".
Wednesday's service will feature a mandate from the King - as supreme governor of the Church of England - giving instruction to install Dame Sarah.
In nods to the diversity of the Anglican Communion, various languages will feature in the service, including singing in Urdu, a Gospel reading in Spanish and a prayer in the Bemba language of Zambia.
Prime Minister Sir Keir Starmer and Conservative Party leader Kemi Badenoch are expected to be present, with other faith leaders, charities, healthcare workers and schoolchildren.
Dame Sarah, who was chief nursing officer in England before she was ordained, has also invited NHS nurses and carers working in hospitals and hospices in Canterbury to attend the ceremony.
Other guests will include more than two dozen primates from the Anglican Communion - Christian churches around the world of which Dame Sarah is now the spiritual leader.
Among these will be some of the first female Anglican bishops from across Africa, who will join a procession through the cathedral.