Jennifer Lopez wasn't afraid to laugh at herself -- or her post-baby figure -- after welcoming Emme and Max (her twins with husband Marc Anthony) in February 2008.

"I remember my flabby belly hanging out right after I gave birth," Lopez, 40, confides in the new issue of Us Weekly. "I kind of laughed and said to Marc, 'Look, baby! Isn't this crazy?' I just didn't care."

The superstar -- just named Us Weekly's Style Icon of the Decade -- admits that she feels differently about that "belly" in hindsight. "I look back at pictures from that time, and I'm like 'Oh, god, I was fat. I was still heavy eight months out!'"

It was Emme and Max who finally inspired Lopez to get her famous body back and shed 50 pounds. The star of The Back-Up Plan explains: "You get to the point where you're like, Where am I? What happened to me? I got to get myself together for my kids, you know? They need to know what I really look like."

Not that everything is exactly as it was before she became a mom. Although she's "back to the size I was before I had the babies," Lopez says her "rib cage" shifted while carrying her son and daughter. "Before I was always able to fit into sample-size clothes from designers, and now they have to take them out just a bit...It's no big deal."

For more of our exclusive interview with Lopez -- including her step-by-step meal and fitness plan, her "tough" experience with a Master Cleanse, her biggest red-carpet regret, her secret to a happy marriage and more on the twins -- pick up the new Us Weekly, on newsstands today!