LONDON - Large crowds gathered on the grand red road leading to Queen Elizabeth's sumptuous London palace on Monday for a pop concert to celebrate her 60 years on the throne, but preparations were overshadowed by news her husband had been admitted to hospital.
Prince Philip, who is 90, was taken to hospital with a bladder infection in what Buckingham Palace said was a "precautionary" move.
He will remain under observation for a few days, meaning he will miss the latter stages of the queen's Diamond Jubilee celebrations, but the BBC said the monarch would attend Monday's gig featuring Paul McCartney and Stevie Wonder among others.
On Tuesday the queen will attend a service of thanksgiving at St Paul's Cathedral, lead a carriage procession through the streets of London and finally wave to huge crowds anticipated beneath the balcony of Buckingham Palace.
Ahead of the jubilee gig staged outside her 775-room London residence, the Mall was awash with Union Jack flags as a good-natured crowd of all ages gathered to watch the performances either on stage or on giant screens erected nearby.
"I'm very excited. It's just brilliant that's she's been with us for so long .... It makes you feel great to be British. Everybody likes her," said teacher Sally Conway, 47, wearing a Union Jack hat, while her mother wore a flag-themed feather boa.
The concert, starting at 1830 GMT, takes place a day after more than a million people braved heavy rain to watch a 1,000-strong flotilla make its way down the River Thames through the heart of London, led by the queen aboard a gilded royal barge festooned with flowers.
The festivities have demonstrated the renewed popularity of a royal family once mired in scandal and dismissed as outdated, and the celebrations over an extended holiday weekend are a boon for Britons battered by recession and harsh state spending cuts.
Coverage in Britain's often fractious newspapers was gushing: "After 60 years on the throne the Queen is, more than ever, an embodiment of our pride and a focus of our patriotism," The Times said its souvenir jubilee edition.
POP ROYALTY SINGS QUEEN'S PRAISES
Music stars performing at the evening concert lined up to sing the 86-year-old queen's praises.
"The monarchy has taken quite a lot of hits in its time. And we turned a corner, it seems to me, when William and Catherine got married," singer Cliff Richard told Sky News, referring to last year's wedding of Elizabeth's grandson Prince William to Kate Middleton, an event that boosted the royal family's image.
Welsh crooner Tom Jones said his set would include "Mama Told Me Not to Come", while Shirley Bassey will sing "Diamonds Are Forever" and Ska band Madness will sing 1980s hit "Our House" from the palace roof.
The BBC promised "one of the most spectacular shows ever staged in the UK". Television viewer figures are expected to be large, after Sunday's flotilla attracted an average audience of 10.3 million, or 60 percent of viewers, the BBC said.
Take That frontman Gary Barlow was brought in to organise the concert, and has penned a song for the jubilee with musical impresario Andrew Lloyd Webber. Barlow said he had received requests from the royal household for particular artists.
"What we've tried to do musically is pick that span right across her reign, someone from every decade of the 60 years, and so we're really hopeful for a really momentous and celebratory occasion," Barlow told the BBC.
The souvenir album "Sing", featuring acts from across the Commonwealth of mostly former British colonies, went straight to number one in the album charts on Sunday.
After the concert, a network of 4,000 beacons will be lit across Britain and the Commonwealth, leading into Tuesday, the final day of the extended holiday weekend.
By 1500 GMT, beacons had already been lit in Tonga, New Zealand and Australia.
Millions of Britons have spilled onto streets bedecked in Union Jack bunting up and down the country for outdoor parties during the jubilee holiday.
Support is not universal however. Views range from indifference - about two million Britons travelled abroad to benefit from the extra days off - to outright opposition.
"Her achievement is just staying alive, doing little and saying less," Graham Smith, head of campaign group Republic, told Reuters.
Elizabeth is only the second monarch to mark 60 years on the throne - her great-great-grandmother Queen Victoria reached the milestone in 1897. She is also on course to become the longest-serving British sovereign in 2015.
The queen's reign began in 1952, when she was 25, and has spanned 12 prime ministers from Winston Churchill to David Cameron.