Dame Shirley Bassey and Gary Barlow OBE will perform for the Queen at the star-studded show to celebrate her 90th birthday.
The Queen's 90th Birthday Celebration will feature leading figures from the world of entertainment and an equestrian spectacular which will be broadcast live on ITV in May.
Dame Shirley, 79, has sung before the monarch on several occasions including for the Royal Variety Performance and during The Queen's Diamond Jubilee Concert at Buckingham Palace in 2012.
Take That's Gary, 45, was chosen to compose the Queen's official Diamond Jubilee single, Sing, with Andrew Lloyd Webber. He performed the song with the Military Wives at The Queen's Diamond Jubilee Concert.
Dame Shirley and Gary will join previously announced performers pop princess Kylie Minogue, tenor Andrea Bocelli, opera singer Katherine Jenkins and pop star Jess Glynne at the televised event, as the nation celebrates the milestone of its longest-lived monarch.
Ant and Dec will host the concert which will also include an appearance from Dame Helen Mirren, who won an Oscar for her portrayal of Elizabeth II in 2006 film The Queen and an Olivier for playing the monarch in The Audience.
The celebration, taking place in the private grounds of Windsor Castle, will tell the story of the Queen's life from her birth in 1926, through the Second World War, to her coronation in 1953 and a reign spanning more than 60 years.
Other stars making an appearance will be singer Alfie Boe, Star Wars leading man John Boyega, singer-songwriter James Blunt and Downton Abbey star Jim Carter.
Also performing will be soul singer Beverley Knight, actor Martin Clunes and Wolf Hall star Damian Lewis.
Absolutely Fabulous comedian Jennifer Saunders, stage and screen actress Imelda Staunton and presenter Alan Titchmarsh will also participate in The Queen's 90th Birthday Celebration.
Hosts Ant and Dec said: "We are honoured to be hosting this special celebration of Her Majesty the Queen's 90th birthday."
"This spectacular evening will bring together some of the best known names in the entertainment world who will perform with 900 horses and 1,500 participants to mark this very special birthday."
Performers in the arena will include The Oman Royal Cavalry, Chilean Huasos and Dancers, The New Zealand Army Band, The Royal Canadian Mounted Police, Azerbaijani Dancers and Djigitovka Horses and Riders, State Carriages from The Royal Mews, The South Australian Police Band, The King's Troop Royal Horse Artillery, The Fijian Armed Forces Band and Dancers, 100 Military and Commonwealth Pipers and The Household Cavalry Mounted Regiment.
The Queen's 90th Birthday Celebration will be broadcast on ITV on May 15.