The coronation service has remained traditional with little change in one thousand years.

But the weekend will include personalised details to reflect King Charles' passions and values including an album to celebrate his love of music and a focus on environmental concerns.

The coronation will be in the evening for Aussies with about three hours of pageantry broadcast live from London.

Recent tumultuous years for the royals will have spectators on the lookout for any sign of tension in the royal family.

Here's what you need to know about the historic event and how Australians will feature.

Coverage of the coronation will begin on TV channels in Australia between 4pm to 5pm AEST on May 6.

The procession from Buckingham Palace is expected to leave at 7.20pm Sydney time with the service to begin at Westminster Abbey at 8pm.

The event will wrap up after the royals appearance on the Buckingham Palace balcony about 10.30pm

The coronation of King Charles III will be released as album the first time a recording of a major historic ceremony will be available to international audiences.

Decca Records said it would record the May 6 service at Westminster Abbey and pre-service music as "The Official Album of the Coronation".

The release will be available for streaming and download soon after the ceremony and a physical version will be released on May 15, Decca Records said.

The four hour album will include speeches and music from ceremony including 12 original compositions from music icons including Andrew Lloyd Webber.

King Charles, who has spent a lifetime campaigning for sustainability and against a throwaway economy, will wear clothing previously worn by his predecessors, including his mother and grandfather, for his coronation.

Many of those items, such as the crowns and sceptres, date back centuries.

King Charles will also be re-using some garments that have appeared at coronations since 1821 "in the interests of sustainability and efficiency", Buckingham Palace said.

Among the vestments to reappear will be the coronation glove made for his grandfather, George VI.

During the ceremony, the glove, made of white leather embroidered with gilt metal thread, is placed onto the right hand of the monarch during the ceremony as a reminder that the sovereign should exercise gentleness in raising taxes.

Charles will also wear his grandfather's Colobium Sindonis - a white linen shift-like tunic, and the sword belt he wore, again eschewing the tradition of having a new one made.

Other regalia Charles will don during the service, whose roots date back 1000 years to his Norman predecessors, includes the "supertunica" - a full-length, sleeved coat of gold silk made for the coronation of King George V, Charles' great-grandfather, and worn by subsequent monarchs including Elizabeth.

Over this, he will wear the Imperial Mantle, made of cloth of gold and originally produced for the coronation of George IV in 1821.

"They are fairly heavy to wear," said Caroline de Guitaut, Deputy Surveyor of the King's Works of Arts.

Prime Minister Anthony Albanese is expected to publicly swear allegiance to King Charles at his coronation after extending an invitation for the monarch to visit Australia.

The prime minister had a private audience with King Charles at Buckingham Palace in London ahead of the coronation.

"It was a pleasure to meet King Charles III again at Buckingham Palace and an honour to represent Australia at his coronation," Mr Albanese said after the meeting.

Mr Albanese reiterated during the audience that the King and other members of the royal family were welcome to visit Australia.

Prominent Indigenous Australians have joined with leaders across the Commonwealth urging King Charles III to formally apologise for the effects of colonisation.

Ahead of the King's coronation, representatives from 12 countries have written a joint letter calling for reparations, acknowledging the impact of slavery, along with returning the remains of Indigenous people and cultural artefacts.

Australian signatories of the letter include Nova Peris, the first Indigenous woman elected to federal parliament, and the co-chair of the Australian Republican Movement, fellow ARM co-chair Craig Foster, as well as Victorian independent senator Lidia Thorpe.

"We stand united in engaging a process to right the wrongs of the past and to continue the process of decolonisation," the letter said.

"We, the undersigned, call on the British monarch King Charles III, on the date of his coronation being May 6, 2023, to acknowledge the horrific impacts on and legacy of genocide and colonisation of the Indigenous and enslaved peoples."

Countries represented in the joint letter include New Zealand, the Bahamas, Canada, Papua New Guinea, Jamaica and Saint Lucia.

The letter called for the King to start the conversation about "slavery's enduring impact", as well as "immediately commit to starting discussions about reparations for the oppression of our peoples".

Senator Thorpe said the effects of British colonisation on Indigenous people were still being felt.

"The genocidal project that commenced in 1788 still continues, and neither the British Crown nor the Australian government have been held to account for the crimes they have committed," she said.

"This country has a new king. The parliament and the prime minister are subjugated to someone we didn't elect. We don't need a new king, we need a head of state chosen by the people," Senator Thorpe said.

King Charles III and Queen Consort Camilla will leave Buckingham Palace about 10.20am London time (7.20pm in Sydney) in a procession to Westminster Abbey.

The couple will travel in the Diamond Jubilee State Coach, built by Australian Jim Frecklington, in celebration of Queen Elizabeth II's 60th year on the throne in 2012.

The formalities will begin as the Archbishop of Canterbury leads the two-hour long service.

The King will be crowned with the 362-year-old St Edward's Crown, while the Camilla will use Queen Mary's Crown.

After the service the King and Queen Consort will return along the same route to Buckingham Palace in a much larger procession.

The Royal Family will then appear on the balcony at Buckingham Palace about 1.30pm London time; 10.30pm in Sydney.

From cocktails to canapes and gala balls to sumptuous feasts, Australia's monarchists are preparing to celebrate in style as they mark the coronation of King Charles III.

A series of events have been organised across the country for the coronation weekend.

Millions of Australians are expected to watch the televised proceedings which will feature a level of pomp and pageantry most have never witnessed before in their lives.

In London, the May 6 ceremony is likely to be more modest compared to those of the past, a one to two-hour event with a mere 2000 guests, a far cry from the lavish three-hour ceremony in front of 8000 when the Queen was crowned in 1953.

Around 5,000 members of the British armed forces will participate in the coronation of King Charles.

They will be joined by soldiers from more than 30 Commonwealth countries to form one of the largest ceremonial military operations in decades.

Gun salutes will sound out across the country to mark the moment the king is crowned, before military personnel conduct a flypast of more than 60 aircraft.

"From the procession on The Mall, to the flypast over London, with gun salutes at sea and across the country, it will be a spectacular and fitting tribute," Defence Secretary Ben Wallace said in a statement on Sunday.

The King and Queen Consort will ride in two coaches on their coronation day - the Australian-built modern Diamond Jubilee state coach and the less comfortable but equally grand 260-year-old Gold state coach.

Charles and Camilla have personally decided to make their two kilometre outward journey - known as the King's procession - from Buckingham Palace to Westminster Abbey on May 6 in the more comfortable Diamond Jubilee state coach.

The black carriage with gilded decorations is the newest in Buckingham Palace's Royal Mews.

First used by the Queen at the state opening of the UK parliament in 2014, it has shock absorbers to stop it from swaying, and heating, internal lights and power windows.

The carriage is more than five metres long, weighs over three tonnes and needs six horses to pull it.

Britain's coronation ceremony originated in medieval times as an essential rite of passage on the journey to becoming king or queen.

But while the crowning of the new monarch is seen as the highlight of the ceremony, the most important moment is actually the "unction", the sacred act of anointing a monarch with holy oil.

This custom can be traced as far back as the seventh and eighth centuries and signals the monarch has been chosen by God.

The UK remains the only European monarchy to retain such a ceremony.

British sovereigns now succeed immediately under law - Charles III is already king even before he is anointed and crowned.

The main elements of a coronation come from the crowning of the Saxon king Edgar the Peaceful, the first King of all England, at Bath Abbey in 973.

The ceremony was devised by Saint Dunstan, the then Archbishop of Canterbury, and established the blueprint for all coronations to follow.

Coronations emerged from the European tradition of increasing church involvement in the state, as well as demonstrating stability in a bid to settle disputes over who should succeed to the throne.

Almost every monarch for nearly 1000 years has been crowned at Westminster Abbey, since William the Conqueror in 1066.

The exceptions are Edward V, one of the Princes in the Tower, who was placed in the Tower of London in 1483 by the future Richard III and never seen again, and Edward VIII, who abdicated in 1936. Neither was crowned.

Before Westminster Abbey was built there was no fixed location for coronations, but William the Conqueror is thought to have chosen the church for his own to reinforce his claim as the legitimate successor of Edward the Confessor, who ordered its building.

In the 14th century the highly decorated illustrated manuscript The Liber Regalis, or Royal Book, which is still kept in the abbey, was made as an instruction manual to help people run and organise a coronation.

Its basic running order for the Christian ceremony remains the same.

The Coronation Oath, in which the monarch swears to govern the peoples of the United Kingdom and the Commonwealth realms "according to their respective laws and customs" is the only aspect of the ceremony that is required by law.

Australia will be represented by Prime Minister Anthony Albanese, Governor-General David Hurley and the state governors.

Fourteen notable Aussies are also on the exclusive guest list including Matildas' star Sam Kerr who has been named flag bearer.

Months of speculation over whether Prince Harry and Meghan Markle would attend was put to rest just weeks before the event.

Meghan and children Archie and Lilibet will remain in California while Prince Harry reunites with his family for the first time publicly since the release of his memoir Spare.

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The Coronation concert will be broadcast live from Windsor Castle, England, on May 7 (UK time).

Stars Katy Perry, Lionel Richie and classical singer Andrea Bocelli are set to take the stage.

Pre-recorded sketches are also planned with the BBC revealing actor Tom Cruise and children's character Winnie the Pooh will feature.

A youth choir from Bunbury, Western Australia, will be part of a pre-recorded mash-up to be played during the concert.

Channel 7 is broadcasting the concert in Australia at 7.30pm AEST on May 8.

- with Australian Associated Press