Diana Ross and George Ezra will headline a star-studded concert later at Buckingham Palace marking the Queen's 70 years on the throne.
The Party at the Palace on Saturday evening will also see Prince Charles and Prince William making speeches to pay tribute to the Queen.
The Queen is not expected to attend the gig; Coverage starts at 19:30 BST.
The Queen has been experiencing mobility problems in recent months and the palace had warned in advance that the monarch would consider which jubilee events she felt able to attend.
She had to pull out of Friday's jubilee thanksgiving service after experiencing "discomfort" during Thursday's events.
She has also not been to the Derby meeting at Epsom on Saturday afternoon and will instead watch the race on TV from Windsor, Buckingham Palace said. But Princess Anne is at the racecourse. She arrived to cheers as part of a procession with her husband and family.
The concert tonight - broadcast live on BBC One - will take place in front of Buckingham Palace, with an expected crowd of about 22,000, plus millions watching on TV.
Stars including broadcaster Sir David Attenborough, tennis player Emma Raducanu, former footballer David Beckham and comedian and writer Stephen Fry will also feature, and there will be a specially-recorded performance from Sir Elton John.