The star of the upcoming I Don't Know How She Does It makes us beg the obvious question: How does she do it?

The mother of three young kids — two-year-old twins Marion and Tabitha stopped by our photo shoot and loved Mom's frilly Christian Siriano skirt (see her in it below!) — manages to balance, well, a lot.

"I love, love, love being an actor," she says. "It's still the hardest and scariest thing I do, outside of parenting. But I've always been someone who likes a busy day. I love the opportunities, and if I can manage my time and the children are okay and we're okay, it's hard to say no…"

Her strategy? Keeping things simple with hubby Matthew Broderick.

We don't talk about our marriage a lot, which is probably wise," she admits. "There are so many other things in our lives that take precedence over the splitting of the atom of our marriage."

For more, pick up a copy of the September issue of Marie Claire, on newsstands August 16. And check back at MarieClaire.com next week for seriously hot, exclusive photos from her stunning cover photo shoot.

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