Simmons said his goal was to get Jackson and Prince to join the line-up of stars on stage for a finale rendition of the 1985 Live Aid anthem We are the World, which Jackson co-wrote.
"They haven't said no. Until they say no, I'll keep dreaming," he said.
The Philadelphia show, from 1am to 7am Melbourne time tomorrow, will feature Beyonce Knowles, Alicia Keys and rapper Jay-Z.
The bill reads like a who's who of the music world, featuring U2, Madonna, Stevie Wonder, Coldplay, Sir Elton John, Sir Paul McCartney, REM, Sting, Justin Timberlake and Robbie Williams."
Tag: live 8