Perry chose Newton after Carey dropped out less than a week before shooting was to start for the movie "For Colored Girls Who Have Considered Suicide When the Rainbow is Enuf," People Magazine reported.
After Carey quit, Perry wrote in a letter to fans, "I said (to Carey), 'What? You're kidding me? It's five days before she has to go.
Perry said Carey's doctor had advised her not to perform in the film.
"I was told that we got a call, saying that even though our deal was done, she had been advised by her doctor not to do the film," Perry wrote. "I said, 'What? You know I want a doctor's note, don't you?"
Some have speculated Carey is pregnant.
Britney Spears debuts 'Perfume' video
Video of Victoria’s Secret models trying to 'twerk' hits Instagram