Royals have joined the street celebrations in London as coronation day kicked on with 50,000 ‘Big Lunch’ parties and a star-studded concert.

Amid pomp and pageantry, the King and Queen were crowned at London’s Westminster Abbey on Saturday in Britain’s biggest ceremonial event for 70 years.

Buckingham Palace said the monarch and his wife were “deeply touched by the events of yesterday”.

The King and Queen were “profoundly grateful both to all those who helped to make it such a glorious occasion — and to the very many who turned out to show their support in such numbers in London and further afield,” a representative said.

Senior members of the family were out in force on Sunday.

Heir-to-the-throne Prince William and his wife Kate thrilled crowds by dropping into a ‘Big Lunch’ party in Windsor.

The King’s younger brother Prince Edward, his sister Princess Anne and his nieces Princess Beatrice and Princess Eugenie also attended ‘Big Lunch’ events.

Prince William and the Princess of Wales drop in on a ‘Big Lunch’ street party. Photo: AAP

Prime Minister Rishi Sunak was among those hosting a coronation lunch, with the guests including Ukrainian families, youth groups and US first lady Jill Biden.

“Come rain or shine, thousands of friends and neighbours are coming together this weekend to put up the bunting, pour the tea and cut the cake at street parties and community events across the UK,” Mr Sunak said.

Later, the King and Queen and other senior royals joined an audience of 20,000 members of the public and invited guests for the “Coronation Concert” on Monday morning (AEDT) at Windsor, the King’s palace to the west of London.

Among those performing were Take That, Nigerian singer-songwriter Tiwa Savage and pianist Lang Lang. Hollywood actor Tom Cruise, British actor Joan Collins and Winnie the Pooh also featured.

The festivities included a “Lighting up the Nation” event, with projections and laser displays illuminating landmarks and areas of natural beauty across the country.

Not everyone has celebrated the coronation, with anti-monarchists angered after being detained for hours on Saturday for planning to protest.

Police said they believed the protesters intended to disrupt the royal procession.

Responding to questions raised over whether the police response had been disproportionate and curtailed the right to free speech, Culture Minister Lucy Frazer said she believed the police had overall “managed to get that balance right”.