AceShowbiz -

Celine Dion impressed fans with her performance of "Immortality" at CBS Special "Stayin' Alive: A Grammy Salute to the Music of the Bee Gees", but her backstage behavior was reportedly highly disturbing to staffers. According to an on-set snitch, she "acted like the tribute was for her!"

According to the insider, Celine "was a total b***h to everyone." The insider tells Radar Online, "She just acted like she was so above everyone else that was there."

A #GRAMMYSalute To The Music Of The #BeeGees. Céline perform "Immortality". Hommage à la musique des BeeGees. Céline interprète «Immortality». -Team Céline #SaturdayNightFever #CélineDion Dress: @eliesaabworld Shoes: @jimmychoo

A post shared by Céline Dion (@celinedion) on Apr 16, 2017 at 5:12pm PDT

Celine took a selfie with Tory Kelly at the event and according to the insider, she was not as cordial to other celebrities backstage as she was with Tory.

Un #selfie dans les coulisses avec Céline et @torikelly / Backstage #selfie with Céline and @ToriKelly before their perfomances! -Team Céline #GRAMMYSalute #BeeGees

A post shared by Céline Dion (@celinedion) on Apr 17, 2017 at 11:39am PDT

"She completely blew people off when they tried to talk to her after her performance," the insider adds, "Celine demanded two dressing rooms and did not want to sit in the audience like the rest of the celebrities were asked to do, which is normal for this type of event."

A representative for Celine hasn't responded to a request for comment.