"It's amazing these great singers are clearing their schedules to make this happen," Cowell told the paper, which is helping to organize the single. "I just found out Mariah has changed her schedule to be able to do this too."
Carey's and Cyrus' participation in the single could not be confirmed at press time, but an Island Def Jam rep did verify the news of Bon Jovi's appearance.
"It says such a lot that everyone is working so hard to help Haiti," Cowell told the Sun. "This is something that really matters to us all, and I'm so grateful for the support we are getting."
An unidentified source close to Cowell told the paper that Carey was very eager to pitch in on the all-star project. "Mariah was brilliant, she wanted to help in any way she could," the source said. "Her name gives the single another great boost."
The recording of the song kicked off in London over the weekend with "X Factor" judge Cheryl Cole and British act JLS, whose Oritse Williams lost relatives in the 7.0 earthquake that has so far claimed the lives of at least 150,000. Also expected to record their bits soon are Take That, Michael Bublé, Westlife, Alexandra Burke, James Morrison, Mika and James Blunt. All proceeds will be split between the Sun's Helping Haiti fund and the official Disasters Emergency Committee appeal. It has not yet been announced when the single will be released.
Friday night's all-star "Hope for Haiti Now" event has set a record for funds raised by public giving by a telethon with $58 million and counting. The iTunes album of the music from the show has already hit #1, notching the biggest one-day album pre-order in iTunes history.