No, they were not trying to edge out would-be idols, and their campaigns wouldn't say if they had any material; the White House hopefuls were expected to champion humanitarian causes on the program.

It is the first time in this presidential campaign that the three vying to be commander-in-chief unite for a common cause.

The three US senators will make videotaped appeals for viewers to donate to worthy charity organizations.

Many stars also have signed on to the Fox television show including Victoria and David Beckham, Jim Carrey, Reese Witherspoon, Julianne Moore, Whoopi Goldberg, Bono, Celine Dion, Forest Whitaker, Jennifer Connolly, Mariah Carey and Robin Williams.

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