King Charles III will be officially proclaimed Britain’s monarch on Saturday in a ceremony steeped in ancient tradition and political symbolism — and, for the first time, broadcast live.

Charles automatically became king when his mother, Queen Elizabeth II, died on Thursday, but the accession ceremony is a key constitutional and ceremonial step in introducing the new monarch to the country.

The ceremony at St. James’s Palace, a royal residence in London, is attended by the Accession Council, senior politicians and officials who advise the monarch. They will meet without Charles to proclaim him sovereign — officially confirming his title, King Charles III — before the king joins them to make a series of oaths and declarations.

“We meet before King Charles comes, decide he’s going to be the new monarch, and then he will come in and we proclaim him,” lawmaker Harriet Harman, a member of the council, told the BBC.

Charles will be accompanied at the ceremony by his wife Camilla, the Queen Consort, and his eldest son Prince William. William is now heir to the throne and known by the title Charles long held, Prince of Wales.

After the ceremony, an official will read the proclamation aloud from a balcony at St. James’s Palace. It will also be read out in the medieval City of London and at other locations across the U.K.