Celine Dion and Josh Groban

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In 2002, Celine appeared on the show to sing the praises of one of our most requested guests—Josh Groban!

These vocal powerhouses first performed together during the 1999 Grammy® Awards, when music producer David Foster asked Josh to fill in for Andrea Bocelli and sing "The Prayer" with Celine.

So I see this young kid, and I'm like, 'Okay, sure and you know the song?' And he said, "Yes, I think do." And he took the microphone and when he started to sing, he couldn't be any more powerful than that," Celine said. "This kid was incredible."

Watch as our cameras follow Grammy-winning artist Josh Groban backstage after an Oprah Show taping.