J.Lo at 40: How a Diva Was Made!

In 40 photos, see how the birthday girl (on July 24) went from Jenny from the Block to superstar

HOT MAMA!

Now that's how you make a red-carpet comeback. In her first public appearance after welcoming her twins, Lopez dazzles at the Metropolitan Museum of Art's Costume Institute Gala in May. She got her body back by working out three times a week with trainer Gunnar Peterson. "She looks great," he said. "If you're in terrific shape to start with, it's easier to get back into shape post-pregnancy."