Singer Mariah Carey, who has just given birth to two beautiful twins in April via C-section, is showing off her post-baby figure, after successfully losing 30 pounds in three months. When talking about her pregnancy, Carey, who had to deal with gestational diabetes and severe edema during pregnancy, says that she could barely walk due to her weight. 　　"I knew I was going to gain weight during the pregnancy, but I didn't think about the pain the weight would cause," she said. "I didn't know if I was going to be able to walk again ... I couldn't get up out of my chair alone." 　　How did she slim down? Carey says that her regimen consists of a strict 1,500-calorie-per-day intake and three workouts a week, not including chasing after the twins. 　　Besides showing off her impressive post-baby body, the Grammy winner also reveals that she's now working on her new music, which is partly inspired by her pregnancy. 　　The 42-year-old diva, who's known for her five-octave range, says her voice has gotten even stronger than before, thanks to pregnancy, 　　"Right now I feel like pregnancy actually helped me vocally," "At this moment my voice is in great shape."Mariah Carey has also teamed up with Justin Bieber on the "All I Want For Christmas Is You" duet, which has been included in Bieber's latest album "Under The Mistletoe."