Will Young, James Morrison and Scouting for Girls have been confirmed as new additions to the lineup of the Visa London 2012 party.
The one-off event, held on Sunday August 24th, will mark the moment at which London takes up the mantle of the official Olympic city.
Some 40,000 people are to attend the party in The Mall in central London, featuring performances from Katherine Jenkins, Il Divo, McFly and The Feeling.
And Brit award-winners Young and Morrison will also be joined by piano-pop newcomers Scouting for Girls as the UK celebrates the handover of the Olympic flag, marking the start of London's tenure as the host city for the 2012 summer Olympic Games.
"This will truly be one of the most memorable events that we have ever performed at, and we are so happy to be involved," said Scouting for Girls following the announcement.
"Our nation should feel very proud to be the next host city for the Olympic and Paralympic Games."
And James Morrison - who yesterday announced that his new single and second album are due for release in September - added: "Being involved with the Olympic Handover celebrations, and playing in front of Buckingham Palace to thousands of people is going to be amazing.
"It's one of those once in a lifetime opportunities and I am very excited!"
While tickets to the event have already been allocated via a ballot, the public will be able to watch the performances via the Live Sites network of public giant television screens.