Here is a post from a Celine Dion forum on the last American Idol show called "Idol Gives Back" we found on the FECC forum:
First off ... she said it was amazing. Celine sang a song WITH Elvis called "If I Can Dream." Much like her duet with Mr. Sinatra but using an Elvis Impersonator from Vegas for the on-stage person.
Sounds complicated ... I agree, but she said they were going to actually use the REAL Elvis's face and voice, which is why she prerecorded the performance.
The Idols do come on stage through the song doing back-up vocals. They were dressed in all white. Celine wore all black, blazer type top with a shear/mesh type top underneath, hair down and long ... loose curls/flips here and there.
She said Celine was in perfect voice and sweet as could be, even after performing it 5 or 6 times. This will air Wednesday the 25th.
Update April 21, 2007:
Celine Dion will raise the dead on Wednesday (25Apr07) when she performs a duet with ELVIS PRESLEY on American Idol. The odd couple will perform Presley's hit If I Can Dream during the upcoming Idol Gives Back charity benefit. Dion has been rehearsing for her odd live collaboration with a Presley impersonator, according to TMZ.com. The Canadian singer will perform with a virtual Presley on the show. The Idol Gives Back special will help raise money to fight extreme poverty in the US and Africa.
Update April 24 2007 from the EPE site:
Are the rumors about Elvis, Celine and the American Idol finalists true? Well, we officially cannot confirm or deny, but we definitely encourage all Elvis fans to watch this week's "Idol Gives Back" edition of the competition show (Tuesday, April 24) and especially the star-studded 2-hour "Idol Gives Back" results show special (Wednesday, April 25).