The 46-year-old singer said she is thrilled that her friend, who already has five-year-old daughter Blue Ivy, is expecting two babies with husband Jay Z, reported E! online.
"The last time I saw her, I was doing my Christmas (show in New York City,) and she came to my show and brought her daughter. It was really, really sweet. I just wish her and Jay all the best.
"It's really hard having twins. I just mean in general, going through the physicality of having twins was really, really difficult for me. I had a tough time," Carey said.
"There's nothing like it. They're the best.