Ellen DeGeneres has dropped out of the Idol Gives Back special that is set to tape this Sunday due to a scheduling conflict with her own show. There is no word yet on who will join Ryan to Seacrest to co-host the special, but I'm sure it won't be too tough to find a replacement considering the people involved.

Celebrities and musicians confirmed:
Robin Williams
Snoop Dogg
Drew Carey
Adam Sandler
Hart
John Legend
Billy Crystal
Maroon 5
Chris Daughtry
Carrie Underwood
Gloria Estefan
Celine Dion
High School Musical's Ashley Tisdale and Vanessa Hudgens
Annie Lennox
Eli and Peyton Manning
Fergi
Brad Pitt
Reese Witherspoon
Bono
Miley Cyrus
Mariah Carey

*Update: Just got off a call with Nigel Lythgoe and he said as of now there is no co-host, and there probably will not be a co-host...so Ryan is flying solo with all the celebs.