Britain geared up Saturday for a "party at the palace" concert starring Diana Ross and Andrea Bocelli, set to be watched by millions to celebrate Queen Elizabeth II's 70 years on the throne.
The concert is the highlight of the third day of public events to mark the 96-year-old monarch's record-breaking Platinum Jubilee with 22,000 people set to attend in person outside Buckingham Palace.
Motown legend Ross, performing for the first time in Britain in 15 years, is a star attraction at the event, to be held on a purpose-built 360-degree stage outside the queen's central London residence.
Rockers Queen + Adam Lambert will open the concert, with Italian opera star Bocelli and James Bond composer Hans Zimmer also featuring in the line-up.
Other performers include Alicia Keys, Craig David and Rod Stewart, George Ezra and Eurovision 2022 runner-up Sam Ryder. Elton John has recorded a tribute.
The queen -- the longest-reigning monarch in British history -- is not expected to attend the two-and-a-half-hour event in person but will instead watch on television at Windsor Castle.
Her heir Prince Charles, 73, and his eldest son, Prince William, 39, will be in attendance.
On Thursday, the first day of celebrations, the queen made two public appearances to huge crowds from the Buckingham Palace balcony, and then travelled to Windsor to attend a beacon-lighting ceremony.
The effort, after months battling difficulties walking and standing, left her in "some discomfort", Buckingham Palace said.
On Friday, she withdrew from a church service of thanksgiving and also pulled out of attending the 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.
Saturday's concert will be broadcast live by the BBC on radio, television and online from 1900 GMT.
As an open-air event, all eyes will be on the skies and the fickle British weather to see if it can be spared downpours forecast later in the evening.
Jubilee celebrations began Thursday with the pomp and pageantry of the Trooping the Colour military parade to mark the sovereign's official birthday.
Friday's focus was the traditional Church of England service led by senior royals -- and returning Prince Harry and his wife Meghan -- in the hallowed surroundings of St Paul's Cathedral.
On Saturday, the queen wished her namesake great-granddaughter Lilibet a "very happy first birthday" on Twitter, after reportedly meeting Harry and Meghan's second child for the first time in recent days.
The couple, who sensationally quit royal life in January 2020, now live in California.
They are staying in Frogmore Cottage on the queen's Windsor Castle estate while visiting Britain for the jubilee.
Britain made Thursday and Friday public holidays to mark the unprecedented landmark of the queen's reign, which has focused attention on the monarchy's future without her.
Longer pub opening hours, street parties and other events celebrating the queen's central place in the life of most Britons have temporarily lifted the gloom of a soaring cost of living crisis.
Sunday will see more than 10 million people share food at "Big Jubilee Lunch" picnics and a musical and creative public pageant involving 10,000 people.
Ed Sheeran will round off the celebrations Sunday, singing his 2017 hit "Perfect" at the end of the pageant.
'Part of my life'
Ross, who heads to the Glastonbury Festival this month after Saturday's concert, said she was "absolutely delighted to receive an invitation to perform on such a momentous occasion".
Charles has previously revealed that the 78-year-old diva's disco hit "Upside Down" from 1980 was one of his favourite tracks.
Queen guitarist Brian May provided one of the most enduring images from the 2002 jubilee, playing "God Save the Queen" from the roof of Buckingham Palace.
British rocker Stewart, who received a knighthood in the queen's 2016 birthday honours for services to music and charity, said Saturday's gig was "nerve-wracking".
"I've grown up with this woman. I was seven when she came to the throne," the 77-year-old singer told the BBC on Friday.
"She's always been part of my life."