Legendary singers Cher and Celine Dionrocked the stage at last night’s Billboard Music Awards in Las Vegas. And although the two music divas appeared to be friendly on camera, has exclusively learned that the divas dueled behind the scenes. Click through 7 photos to find out why Dion was so upset about Cher.

One day after turning 71 years old, legendary singer Cher belted out her classic hits “If I Could Turn Back Time” and “Believe.” But as fans rejoiced over the mother of Chaz Bono, 48, winning the Icon Award following her performances, a source backstage at the show said that there was one person who was NOT happy – Celine Dion.

As fans know Dion, 49, and Cher have competing shows in Las Vegas. “There is already so much animosity between the two of them,” said the source.

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