The planning and dress rehearsals are over and the King's coronation finally takes place today in Westminster Abbey - here's a step-by-step guide to what will happen.
The ceremony will begin at 11am after the royals arrive in procession from Buckingham Palace and will end around 1pm.
The main elements are the recognition; the oath; the anointing; the investiture and crowning; the enthronement and homage; and the Queen Consort's coronation.
More than 2,000 people will be at the abbey, the site of 38 previous coronations dating back to William the Conqueror in 1066.
Flags representing Commonwealth nations will be carried through the ancient church - with prime ministers, governors and leaders from different faiths also involved.
The royals will arrive on the more modern diamond jubilee state coach and depart on the "bumpy" 260-year-old gold state coach.
They will walk through the abbey to the theatre of coronation, the space between the high altar and the quire stalls which acts at the 'stage' for the big event.
Sitting on the chairs of estate, the service will begin - a moment the King has been destined for since he became heir at age three.
The chairs were made for the Queen and Prince Philip, but have been reupholstered and hand embroidered with the cyphers of the King and Queen Consort.
The King will be greeted by a young chorister of the Chapel Royal and will reply that he comes "not to be served but to serve".
He will stand, head bowed, in a moment of prayer before the Archbishop of Canterbury, Justin Welby, gives the greeting and introduction.
Kyrie eleison will be sung - an ancient prayer used at the beginning of Holy Communion for about 1,600 years. For the first time at a coronation it will be performed in Welsh.
'Your undoubted King': The recognition
This part dates back to the ancient procedures of the Witan - the supreme council of England in Anglo-Saxon times.
The King will be presented to the congregation at each of the points of the compass - with a declaration at each turn.
"I here present unto you King Charles, your undoubted King.
"Wherefore all you who are come this day to do your homage and service: are you willing to do the same?"
The congregation and choir will reply "God save King Charles."
The Archbishop of Canterbury performs the first of the compass-point declarations.
The others will be done by Lady Angiolini - representing the Order of the Thistle; Baroness Amos - representing the Order of the Garter; and Christopher Finney - chair of the Victoria Cross & George Cross Association, representing recipients of bravery medals.
The oath and the King's personal prayer
The King will swear the coronation and accession declaration oaths on a specially commissioned Bible - presented to him by the moderator of the general assembly of the Church of Scotland.
He will promise to maintain the Anglican Protestant Church, rule according to parliament's laws and uphold justice and mercy.
An anthem will be sung before he moves to the high altar to pray aloud in front of the congregation - the first monarch to do so.
A personal prayer, inspired in part by the popular hymn I Vow To Thee My Country, has been written for him.
The Church of England says it is possibly the first time such a personal prayer has been voiced so publicly by the sovereign.
Mass For Four Voices will be sung, followed by a prayer led by the archbishop.
Prime Minister Rishi Sunak will read The Epistle, with Dame Sarah Mullally, the dean of the Chapels Royal, following with a passage from the Gospel.
Female clergy are taking part in a coronation for the first time, with female priests introduced in the Church of England in 1994 and female bishops in 2014.
The Archbishop of Canterbury now takes centre stage with the keynote sermon.
Veni Creator - an ancient text that became part of the coronation in the fourteenth century - is sung, with parts in English, Welsh, Scottish Gaelic and Irish Gaelic.
Preparations are now made for the King's anointing, including a prayer of thanksgiving for the holy oil.
The oil was consecrated by the patriarch of Jerusalem and the Anglican archbishop in Jerusalem.
It was created using olives from two groves on the Mount of Olives, at the Monastery of Mary Magdalene and the Monastery of the Ascension.
The archbishop in Jerusalem will hand the oil to the Archbishop of Canterbury.
Anointed with holy oil - and the Stone of Destiny
The King's robes of state will be removed and he'll move from his chair of estate to the historic coronation chair, used at every ceremony since 1308.
A 152kg sandstone slab, the Stone of Scone - or the Stone of Destiny, is placed inside the bottom of the chair, having been brought specially from Edinburgh Castle.
Kings of Scotland were inaugurated on the ancient stone and its symbolises the shared history and heritage between UK nations.
The anointing screen will be moved in place by troops from the Household Division as the choir sings the anthem Zadok the Priest.
An embroidered tree celebrating the Commonwealth features on the 2.6-metre high screen
The archbishop, helped by the Dean of Westminster and the Archbishop of York, will anoint the King on his hands, chest and head. It takes place in private behind the screen.
The oil is pored from the ampulla - an eagle-shaped vessel - into the coronation spoon - the oldest object in the coronation regalia.
The King will then kneel in front of the high altar as the Archbishop of Canterbury gives a blessing.
Investiture, crown jewels and regalia
The King will put on the coronation robes: the Colobium Sindonis, a sleeveless white linen garment symbolising purity and simplicity; the supertunica, an embroidered gold coat; and the sword belt - or girdle.
They have all been used in previous coronations, with the supertunica worn by King George V, King George VI and Queen Elizabeth II, and the sword belt used by King George VI.
Next, the coronation regalia - the heart of the Crown Jewels and normally kept in the Tower Of London - will be presented to the King by peers from the House of Lords and senior bishops.
Peers from non-Christian faiths will take part for the first time, but only hold regalia that doesn't have explicit Christian motifs.
The first item of regalia will be the spurs, representing knighthood and chivalry. They are brought to the King to acknowledge by the Lord Great Chamberlain and then returned to the altar.
He next receives the jewelled sword from the lord president of the Privy Council, Penny Mordaunt MP, as the archbishop reads a prayer.
It is clipped into his sword belt while there's another reading, before being placed on the altar.
Ms Mordaunt will then 'redeem' the sword by offering a small velvet bag of coins, containing 100 newly-minted 50p pieces featuring the King's image.
It's the first time a woman has carried and presented the sword.
The sword has a double meaning - a symbol of defence of the defenceless, but also of the word of God
The King next receives and acknowledges the gold armills - or bracelets of sincerity and wisdom, presented to him by Lord Kamall.
They are decorated with national emblems, such as roses, thistles and harps, and lined in red velvet.
Prince William will then help present his father with the stole royal - a long, narrow length of cloth worn around the neck, and the imperial mantle - a long gold-coloured robe.
The Bishop of Durham, Baroness Meron and other bishops will also help clothe the King during this section.
Next up is the golden orb, made in the seventeenth century and mounted with emeralds, rubies and sapphires, rose-cut diamonds and pearls.
It represents the sovereign's power and symbolises the world under the cross of Christ.
The Dean of Westminster will hand it to the Archbishop of Armagh, who brings it to the Archbishop of Canterbury, who then places it in the King's right hand.
The monarch's ring is next, presented by Lord Patel.
The King will acknowledge it before it's returned to the altar, with the archbishop announcing that it is a "sign of the covenant sworn this day between God and King, King and people".
The coronation glove is now presented by Lord Singh of Wimbledon, with the King placing it on his right hand.
It's symbolic of the sovereign as advocate and challenger for the protection and honour of the people.
The sceptre with cross and rod with dove are the final items before the crowning.
A huge drop-shaped diamond, Cullinan I, or the Star of Africa, weighing 530.2 carats, is the centrepiece of the sceptre with cross.
Dating back to 1661, it is also mounted with rubies, emeralds and sapphires, and represents temporal power, authority and good governance.
The sceptre with dove is a more plain gold rod that's symbolic of the sovereign's spiritual role, as well as justice and mercy.
The Archbishop of Wales and the Primus of Scotland will pass the sceptres to the Archbishop of Canterbury to place in the King's hands.
Next, the pinnacle of the ceremony arrives: the crowning of King Charles III.
The King's crowning moment and gun salutes
The Dean Of Westminster will hand St Edward's crown to the Archbishop Of Canterbury, who says a prayer of blessing before placing it on the King's head.
He will proclaim "God save the King" - with the congregation echoing his words.
The crown was made for King Charles II in 1661 and is made of a solid gold frame set with rubies, amethysts, sapphires, garnet, topazes and tourmalines.
Westminster Abbey's bells will ring for two minutes.
There will also be a fanfare and a gun salute fired from Horse Guards Parade, the Tower of London, and at saluting stations across the UK - as well as from ships at sea.
Enthronement and Prince William's promise
A blessing by church figures from across the UK follows, before the King is accompanied by bishops and officers of state to his throne chair in the theatre of coronation.
The Archbishop of Canterbury will lead words of fealty to the King on behalf of the Church, promising to be "faithful and true", while Prince William will also give homage.
Historically these homages had great significance in maintaining law and order, while the enthronement represents the monarch taking possession of his kingdom.
The King's eldest son will say: "I, William, Prince of Wales, pledge my loyalty to you and faith and truth I will bear unto you, as your liege man of life and limb. So help me God."
The congregation - and people around the UK and Commonwealth - will be invited to participate in public homage or with a moment of private reflection.
This replaces the traditional homage of peers.
The enthronement section will finish with an anthem, Confortare by Sir Walford-Davies.
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The Queen's coronation and a 'recycled' crown
Attention now falls on the Queen Consort, who will receive her own glittering regalia before being crowned.
The last consort to be crowned was the Queen Mother in 1937.
It's a ceremony that only female consorts receive - hence there was no such ritual for Prince Philip.
The archbishop will mark her head with holy oil, saying: "Almighty God, the fountain of all goodness; hear our prayer this day for thy servant Camilla, whom in thy name, and with all devotion, we consecrate our Queen..."
Unlike for the King, no privacy screen will be used.
She will be presented with a ring, before the Dean of Westminster hands her crown to the archbishop.
To reflect the royals' interest in sustainability, the Queen Consort will use a 'recycled' version of the crown made for the 1911 coronation of Queen Mary - George V's consort - rather than having a new one made, as is usually the case.
In tribute to Queen Elizabeth II, it's been reset with the Cullinan diamonds that she often wore as brooches, said to be known within the Royal Family as "Granny's Chips".
However, the crown will not feature the controversial Koh-i-Noor diamond.
The Queen Consort will then be presented with a sceptre and the rod of "equity and mercy" by the Bishop of Dover and Lord Chartres.
A switch of crown - and Lloyd Webber's anthem
A coronation anthem by Lord Andrew Lloyd Webber, based on verses from psalm 98, will be performed as the Queen Consort takes her place in her own throne chair beside the King.
After another hymn, the couple will remove their crowns and return to the chairs of estate as the bread and wine of holy communion is brought out.
The Eucharist prayer, read by the Archbishop of Canterbury, will accompany the communion, and the Sanctus and Agnus Dei will be sung.
After communion, there will be a final blessing by the archbishop and several other hymns, before the congregation joins in with a rendition of the national anthem.
A change of costume also takes place, as the royals head to the Chapel of St Edward, behind the high altar, to put on their robes of estate.
The King will also put on the imperial state crown - perhaps the most dazzling of the two used during the coronation.
It has 2,868 diamonds, 17 sapphires, 11 emeralds and 269 pearls; including the 317.4-carat Cullinan II diamond and the large oval Stuart sapphire.
The crown was made for the coronation of King George VI in 1937 but is closely based on one designed for Queen Victoria.
The royals' outward procession will see them receive a greeting from leaders and representatives of the Jewish, Hindu, Sikh, Muslim and Buddhist faiths.
It's intended to recognise the religious diversity of the UK and Commonwealth.
They will say: "Your Majesty, as neighbours in faith, we acknowledge the value of public service. We unite with people of all faiths and beliefs in thanksgiving, and in service with you for the common good."
The King will acknowledge their greeting before taking the gold state coach to Buckingham Palace, where the much-anticipated balcony moment will later take place.