New reports are coming in that on the set of "American Horror Story: Coven," cast member Emma Roberts is caught in a feud with Gabourey Sidibe.

"Emma complains about the tiniest things and won't speak to crew members," a witness told Star magazine. "Gabby finally told Emma to cut her attitude and stop being rude."

The alleged confrontation between Roberts and Sidibe reportedly prompted the 22-year-old niece of Julia Roberts to switch up her attitude, though the crew still feels as though "she still acts like she's above everyone else."

Roberts plays Madison Montgomery on the hit TV show, while Sidibe plays "human voodoo doll" witch Queenie.

Despite claims of her bad behavior, Roberts told Clevver News at the red carpet premiere that being on the set of "American Horor Story" is a "dream come true."

"When I was younger I was obsessed with witch movies and Sabrina the Teenage Witch and all of that so to be on a show playing a witch is pretty much one of my biggest childhood dreams come true," she told an interviewer.

This isn't the first time that sources have reported Roberts exhibiting diva-like behavior. Back in August, the actress got flack for reportedly trying to skip the long line at NYC's Dominique Ansel Bakery with her publicist and get a taste of the famous "Cronut", though she was denied and told to stand in the back.

And earlier this month, Jennifer Aniston reportedly was fed up with Roberts over her "hard partying and public blowups," including her highly publicized fight with her boyfriend Evan Peters.