Lily Allen, Rod Stewart and Kanye West have been added to the growing list of performers who will play at the Diana memorial concert at Wembley Stadium.
Allen recently postponed some of her US tour dates
Natasha Bedingfield, The Feeling, James Morrison, Orson and Status Quo have also been confirmed to play at the Wembley Stadium gig on 1 July.
Organisers are releasing an extra 10,000 tickets on Friday morning.
The charity concert will mark the Princess of Wales' 46th birthday and the 10th anniversary of her death.
Other acts previously announced to perform include Sir Elton John, Duran Duran, Bryan Ferry, Joss Stone and Pharrell Williams.
The concert will be in three parts with two 20-minute intervals and will last for five hours.
The event has been organised by Princes William and Harry, who said they wanted it to be "the best birthday present" for their mother.
Proceeds will go to charities Diana supported
Geoffrey Matthews, the concert's project director, said that Prince Harry was still set for deployment in Iraq and that it was likely he would be allowed leave to attend the event.
He added that the princes would appear on stage in some capacity.
He said there was no final guest list regarding which Royals would attend but that the Queen, Prince Charles and the Duchess of Cornwall were not expected to be there.
"It's more of a fun-filled, younger generation event."
The running order and presenters are yet to be decided.
The first 22,500 tickets sold out in minutes when they went on sale in December.
Organisers estimate there will be 62,000 seats in total.
The latest batch of 10,000 tickets, which cost £45 each, go on sale at 0900 BST on Friday via Ticketmaster.
Mr Matthews said some artists wanted to take part but were unable too due to busy schedules, although he declined to name them.
The concert will be shown in 140 countries and will be broadcast on BBC One in the UK. The BBC will also show the live event on big screens around the country.
The English National Ballet and a musicals medley put together by Andrew Lloyd Webber will also feature.
Mr Matthews said the princes had no concerns about the Live Earth concerts, which take place a week later, overshadowing their celebration.
"Live Earth is a cause dear to the hearts of everyone at Clarence House," he said.
More artists and ticket information will be announced nearer the time.