AceShowbiz -

Christina Aguilera's return to "The Voice" reportedly created a nightmare for the show's crew. Radar Online quoted a so-called insider as saying, "Christina is such a terror to work with. She is frequently late and she doesn't even seem to care or apologize for holding up the filming of the show."

"She just has ridiculous demands since coming back as a judge, and everyone is wishing she did not return!" so the source described her "on-set diva antics." The source added, "To make matters worse, she is constantly fighting with Adam [Levine]. They cannot stand each other."

It's additionally reported that NBC actually wanted to have two female and two male judges with either Shakira or Gwen Stefani returning, but Xtina allegedly said "absolutely not, and that she would be the only female judge or she would not do it at all."

Gossip Cop, however, begs to differ. The site brands the story as fake since Christina is currently not shooting "The Voice". The pre-taped episodes were filmed three months ago and the live episodes won't start until April. The singer is now filming her guest appearance on "Nashville" instead.

A source also tells the site the diva rumor is "stupid," adding that "if she is so awful," fellow coach Pharrell Williams would not want to work on an album with her.