LONDON - Some 22,000 people and millions more at home were on Saturday expected at a musical celebration for Queen Elizabeth II’s historic Platinum Jubilee.

The “Platinum Party at the Palace” is the highlight of the third day of public events to mark the 96-year-old monarch’s record-breaking 70 years on the throne.

Motown legend Diana Ross is a star attraction at the event, to be held on a purpose-built 360-degree stage outside the head of state’s central London residence, Buckingham Palace. The concert also features artists including Italian opera star Andrea Bocelli and James Bond composer Hans Zimmer, in a marked shift in tone from the jubilee’s first two days. Celebrations began on Thursday with the pomp and pageantry of the Trooping the Colour military parade to mark the sovereign’s official birthday. Friday’s focus was a traditional Church of England service of thanksgiving led by senior royals -- and returning Prince Harry and his wife Meghan -- in the hallowed surroundings of St Paul’s Cathedral. Saturday’s concert, which will be broadcast live by the BBC on radio, television and online from 1900 GMT, is no less grand in scale. But as an open-air event, all eyes will be on the skies and the fickle British weather to see if the forecast downpours hold off.

The Queen, the longest-reigning monarch in British history -- is not expected to attend the 2.5-hour concert but will watch on television at Windsor Castle.

She made two public appearances to huge crowds from the Buckingham Palace balcony on Thursday, and was then at Windsor for a beacon-lighting ceremony.

The effort, after months battling difficulties walking and standing, left her in “some discomfort”, Buckingham Palace said.

It led to her withdrawing from Friday’s church service and also an expected appearance at Epsom racecourse for the flat-racing showcase The Derby. Her no-show at The Derby on Saturday is only the fourth time the keen horseracing fan, rider and breeder has missed the race since 1952. She did not attend in 2020 as spectators were banned due to Covid.

Her heir Prince Charles, 73, and his eldest son, Prince William, 39, will be in attendance at the concert instead.