Diana concert tickets sell out in 20 minutes

Ten thousand more seats for the event were up for grabs from 9am, but were snapped up soon after going on sale.

The Wembley concert in July marks 10 years since the Princess was killed in a Paris car crash.

Further tickets are likely to go on sale at a later stage.

Eight new acts, including Lily Allen, Kanye West and Rod Stewart were announced by organisers yesterday.

Status Quo, Natasha Bedingfield, The Feeling, James Morrison and Orson will also star in the Princes' tribute to their mother on July 1, which would have been her 46th birthday.

The royal brothers have expressed their thanks to all those who have bought tickets so far.

Geoffrey Matthews, who is in charge of the concert, said: "Prince William and Prince Harry have asked me to say how incredibly grateful they are to the people who bought tickets and the artists who so kindly are going to perform, and the broadcasters who have showed such an interest in their celebrations of their mother."

Other performers include Sir Elton John, Bryan Ferry, Joss Stone, Pharrell Williams and Duran Duran.

Andrew Lloyd Webber is devising a medley of musicals and there will be a performance by the English National Ballet, in keeping with Diana's taste in music and the arts.

The tickets sold out in 20 minutes, Clarence House said.

"It's brilliant. We're really, really chuffed. The demand has been very high," spokeswoman said.

William and Harry will appear on stage at some point during the five-hour event.

Organisers denied the concert team was worried about Live Earth, starring Madonna and other high profile names, at Wembley the next weekend.

"Live Earth is a massive worldwide multi-venue festival which has a fantastic cause and we wish them all the best," Mr Matthews said.

"The concert (for Diana) I think is absolutely unique."

Live Earth will share some facilities left by the Diana team at Wembley Stadium, likely to include the massive stage they are constructing.

William and Harry have yet to finalise their guest list.

It was confirmed in December last year that the Prince of Wales and the Duchess of Cornwall would not be at the event, with aides saying the event was aimed at the younger generation. The Queen is also unlikely to attend.

Instead, the royal family will gather to remember the Princess at a memorial service on August 31 - the 10th anniversary of her death - at the Guards' Chapel in London.

The comperes for the concert have yet to be announced and more artists will be unveiled later.

A crowd of up to 62,000 is expected to pack Wembley to watch the celebration.

The BBC is broadcasting it live and is also likely to play it on giant screens around the country.

More than 140 countries will show the concert, with the worldwide audience expected to reach hundreds of millions.