Lily Allen and The Feeling will provide an injection of youth and indie music at the Princess Diana tribute concert.

The event, at Wembley Stadium on 1 July, had been criticised for its line-up of "has-been" acts with older performers such as Elton John, Bryan Ferry and Duran Duran.

Today organisers unveiled new names designed to appeal to a younger audience. They also announced details of another 10,000 tickets.

Allen, 21, will be the second female singer alongside Joss Stone. Other acts confirmed today include Orson, James Morrison, Kanye West and Natasha Bedingfield. Negotiations are still taking place with some A-list film stars to appear as presenters.

Rod Stewart, one of Diana's favourite singers, and Status Quo have also agreed to take part.

The rest of the line-up includes the English National Ballet, a medley of Andrew Lloyd Webber hits - reportedly featuring Jason Donovan and Donny Osmond - and US rapper Pharrell Williams.

More names will be added closer to the event but, contrary to rumour, Take That will not be appearing because several of the band will be on holiday. Keane are also unable to appear. The Concert for Diana has been organised by Princes William and Harry to mark what would have been their mother's 46th birthday.

Critics have claimed it will be overshadowed by the Live Earth gig at Wembley the following weekend. The global "eco-awareness" event, organised by Al Gore, will feature Madonna, Red Hot Chili Peppers and the Black Eyed Peas among others.

A Concert for Diana insider today hit back at critics, insisting: "The criteria has always been some of Diana's favourites and some of the princes' favourites and I think we've achieved that. There's a very nice balance. Where else can you get Pharrell Williams and the English National Ballet on the same bill?"

The new tickets go on sale tomorrow from 9am via the event's website. All 22,500 of the first tickets sold out within 20 minutes in December. Many appeared for sale on eBay for up to £300 but the auction website quickly removed them "out of respect" for the late Princess's memory.

The remainder of the 60,000 tickets have been allocated to charities and members of the Club Wembley scheme.

The concert will be broadcast worldwide, including on BBC1, with the rights sold to 140 countries.