Mariah Carey Mariah Carey

Mariah Carey gave birth to twins six months ago — and now she's showing off her hot post-baby body.

Photo Gallery: Dramatic celebrity weight loss

Rocking her signature curves in a skin-tight black dress and stilettos, the singer appeared on Tuesday's The Rosie Show to discuss her new, slimmed-down look. She explained that the initial 40-pound loss was water weight, due to a difficult pregnancy.

Mariah Carey gives birth to twins

The 42-year-old singer — who with husband Nick Cannon welcomed twins Moroccan and Monroe Cannon on April 30 — then dropped an additional 30-pounds thanks to the Jenny diet plan (formerly Jenny Craig) — a combination of a 1,500-calorie-a-day diet and working out three times a week. Carey is now a spokesperson for the brand.She told Us Weekly, "The whole point of this is not just like: 'Oh, hey, look at me and my weight loss, I'm fantastic.' It's really health. Like I said, I learned it when I became helpless and felt so vulnerable like never before in my life."