Disney teen star Miley Cyrus gave a huge boost last night to Simon Cowell’s Haiti mercy project. She signed up for his charity single as the music mogul chased other big names to take part. Cowell, 50, has already recruited Take That, JLS, Cheryl Cole and Susan Boyle. But he hopes to bring in superstars such as Sir Paul McCartney, Sir Elton John, George Michael and Robbie Williams, who was in France with his girlfriend Ayda Field yesterday. Cowell hopes to raise millions with a cover single of REM’s Everybody Hurts, to be recorded this week. But last night talks to bring in music heavyweights were said to be at a “delicate stage”. A source said: “The likes of Robbie, Macca, Elton and George are names Simon would love to get involved. “But a lot of stars have been getting a lot of offers from other projects and there are also logistical hurdles to overcome before they agree.”