"Mary Carey and Mariah Carey share the identical surname and have first names that are very similar," the musician's attorney, Robert Becker, wrote. "Confusion between your client and her Mary Carey trademark and our client and its Mariah Carey trademark is therefore likely."
Becker also asked that Mary Carey only use her name for "adult entertainment" purposes, not for singing or performing music.
Mary Carey, aka Mary Cook, has been using the name since 2002 and filed trademark papers earlier this year, is unfazed.
"I'm ready to battle Mariah over this because I've been Mary Carey for a long time," Mary Carey said. "It's kind of funny because I'm a porn star and I've been being myself for a long time. I think she's being silly."
Cook's lawyer, David Beitchman, doesn't think that the Grammy-winning Carey has a chance in court.
"My first thought was, 'Does Mariah Carey realize what her lawyer is comparing her to, and are they seriously concerned?'" he said. "Do they seriously think the fans are going to be confused?"