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Even Jennifer Lopez had trouble getting her glam back after welcoming her twins Max and Emme over three years ago.

"Sometimes you don't even have time to shower, and I totally understand that" the single mom, 42, says in the huge new style issue of Us Weekly, out now.

But her son and daughter inspired her -- then and now -- to summon her inner fashionista. "My kids need to know what I look like! Make an effort and say, 'OK, I need to get back to the person I was."

Her advice to new moms? "Don't stress over it!"

In the extensive Q&A with Us, the singer, actress, designer and American Idol judge also looks back on perhaps her first, and most iconic, style moment in the public eye: That green, plunging-neckline Versace gown at the 2000 Grammys, which she wore as then-beau Sean Combs' date.

One lesser-known fact about that dress? Lopez wasn't the first to wear it.

"I remember putting it on and the stylist saying, 'You know, somebody else wore this,'" Lopez recalls. "I was like, 'I don't care. It looks great.'"

For more of our exclusive chat with Lopez, pick up Us Weekly's biggest style issue ever -- with 52 bonus pages of fall fashion, great buys under $100, celebs' shopping tips and $1,800 in discounts and freebies!